SNOW DRAG RACING
SNOW DRAG specific circuits or classes, but meets 1. A driver that comes to the line and takes
RACING established safety standards, applicable the green flag/light will qualify for points if
laws and/or approved insurance coverage. available to that driver.
OFFICIAL SANCTIONS AND CLASSES Stock 440 FAN STOCK 2. In the finals, the drivers finishing behind a
*Stock Fan disqualified driver will move up to the next
*Stock 440 440cc maximum FAN higher position.
*Stock 500 600cc maximum
Stock 700S 440cc maximum 3. Points shall be awarded as follows:
Stock 800S 500cc maximum
The intent of these classes is to establish Stock 900 (single pipe) FINISHER POINTS EXAMPLE
races in which all can compete at their level of (single pipe) PER CLASS (points for
personal and equipment ability. The class 900cc maximum First
structure is organized in such a way as to Second ENTRY 30 class
enable as many snowmobiles as possible a *These three classes are available for ages 14 Third entries)
place to successfully compete. through 17 Juniors through the ISR Junior Fourth 5 180 (5X30)
advancement program. See Junior Fifth 4 120
Based upon safety and competition, stock Competition chapter. 3 90
snowmobiles manufactured prior to 15 years 2 60
of the current model year will not compete in 1 30
Stock classes, but may compete in other
classes. IMPROVED STOCK 4. In Seniors’ competition, the total points
If class rules are not followed, the class name Improved Stock 440 440cc maximum awarded will be based on the number of
shall not be used and the class shall be run as
a specialty class with ISR’s prior approval. Improved Stock 500 500cc maximum entries up to a maximum of 50.
Competitors must be 18 years of age to IMPROVED STOCK Turbo charged 5. In Women's competition, the total points
compete in these classes. All Stock classes
are open for Junior 16/17 who are advanced OPEN 800 CLASS engines, nitrous awarded will be based on the number of
according to procedures in Junior Competition.
For information, see Junior Novice and Junior (Does not apply to oxide engines entries up to a maximum of 20.
Sections.
Improved Stock 800) allowed. 6. Points will be awarded in any class that
PRO STOCK has one or more entries.
7. Points will be awarded and tabulated by
Pro Stock 500 500cc maximum
each affiliate (or group of affiliates). Points
STOCK CLASSES are non-transferable between affiliates
unless an arrangement has been agreed
CLASS Max. CARBS EXH. HEAVY MODIFIED to by the affiliates involved. Driver must be
cc an affiliate member to receive high point
STOCK 600 OEM (single Heavy Modified 440 440cc maximum awards.
600S pipe) Heavy Modified 500 500cc maximum 8. Points tabulation for ISR Annual Drag
Stock 600 600 OEM OEM Heavy Modified 600 600cc maximum Racing Championship invitations will end
Stock 700 700 OEM OEM Heavy Modified 700 700cc maximum on the weekend before the race.
Stock 800 800 OEM OEM Heavy Modified 800 800cc maximum 9. Point tabulation for circuit high point
Stock 1000 OEM OEM Heavy Modified 1000 1000cc maximum winners and class champions will end at
1000 the close of race season.
OPEN MODIFIED 10. No points will be awarded at the
International Championship race. All other
IMPROVED STOCK CLASSES Open Mod 250 250cc maximum rules and regulations for the International
Open Mod 340 340cc maximum Championships will be set by the ISR
CLASS MAX CARBS Open Mod 440 440cc maximum Executive Drag Racing Committee.
cc Open Mod 500 500cc maximum 11. One-event members will not receive
Imp. Stock 600 OEM for the points.
600 model FOUR STROKE CLASS
Imp. Stock 700 OEM for the
700 model CLASS CC CARB/EFI EXH GENERAL COMPETITION AND SAFETY
Imp. Stock 800 OEM for the RULES
800 model Stock 1200 OEM OEM
Imp. Stock 1000 Any carburetor PADDOCK/STAGING & STARTING LINE
1000 allowed Naturally aspirated only
1. Grooming of the start area and use of
FOUR STROKE ENGINES specialized tools will be at the discretion of
the sanctioning body.
PRO STOCK CLASSES 1. In order to be eligible for two stroke
competition, a four-stroke powered 2. Anybody in this area will be required to
Pro Stock 600 600cc maximum snowmobile must be classified through the wear safety glasses. It is highly
ISR four- stroke classification procedure. recommended that full coverage helmets
and upper body protection be used.
Pro Stock 700 700cc maximum SPECIALITY CLASSES / SANCTIONS
3. It is mandatory that a separate clean out
Pro Stock 800 800cc maximum 3. All special sanctions and specialty classes board be placed near the starting line.
Pro Stock 1000 1000cc maximum must be approved in writing by ISR and
the rules committee before competition. 4. A protective stand will be in place behind
OPEN MODIFIED CLASSES the track of the snowmobile when it is
4. Can be any snowmobile drag racing class leaving the starting line.
Open Mod 600 600 cc maximum or event that does not fall under any of the
Open Mod 700 700cc maximum specific circuits or classes, but meets 5. The driver must start the race with feet on
established safety standards, applicable running boards, stirrups or foot pegs and
Open Mod 800 800cc maximum laws and/or approved insurance coverage. the feet must remain there for the duration
SCORING of the run. If the driver leaves the normal
Open Mod 1000 1000cc maximum driving position, he/she must resume
1. All competitors that show to the line for a proper position before continuing. The
SPECIALITY CLASSES / SANCTIONS final event will be scored. Race Director has the authority to
disqualify a driver who cannot maintain a
1. All special sanctions and specialty classes 2. In drag racing events, in a final, a red light proper driver position.
must be approved in writing by ISR and will constitute a last place finish for prizes
the rules committee before competition. and awards. In the event of multiple red 6. No assistance shall be given to a driver on
lights, the scoring will be based on the starting line except when mechanical
2. Can be any snowmobile drag racing class reaction time. difficulty develops. One (1) mechanic may
or event that does not fall under any of the help the driver with permission from the
DRIVER POINT SYSTEM Race Director. Extra help may be
requested to remove the snowmobile from
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
the course (special events exempt). safety and performance rules in its original 3. (Improved Stock, Pro Stock and Pro Mod)
Starter looks for raised hands, signifying class. The clutch cover must be provided with a
engines not running or other mechanical secure mounting plate. The mounting
trouble. If none, the starter will start the ADDING BALLAST plate must cover the area below the
race within five (5) seconds (special 1. Adding fuel to the fuel tank before a race is clutches (from front of cover to rear of
events exempt). A start will not be cover and width of cover) and be made of
delayed due to mechanical difficulties for allowed as ballast. If fuel does not make the same material as the cover. The cover
more than two (2) minutes from original up for the weight deficiency, additional must be securely fastened to the mounting
notification. If difficulties develop after the ballast must be securely fastened to the plate and the mounting plate must be
green flag drops, the driver may continue snowmobile. Fastener must be at least securely fastened to the belly pan
to race or withdraw; however, if a driver (one) 5/16 inch, grade five bolt with a self-
withdraws to the pit, the driver is not locking nut. No wing nuts allowed. 4. (Heavy Mod and Open Mod) Clutch cover
eligible to restart. 2. No weight belts or loose objects may be must have full facial coverage and 360-
7. If a racing snowmobile is moving under its worn by driver. degree elliptical coverage in the direction
own power, the operator must be wearing of clutch/belt travel (see illustration).
a helmet and the tether must be securely IDENTIFICATION Clutch cover must be .090 inch 6061T6
attached to the operator. 1. The maximum class displacement in cc’s aluminum or equivalent steel material and
8. Moving a running snowmobile on a stand be covered with six (6) inch belting. Other
is prohibited. must be permanently displayed (minimum clutch cover materials not allowed. If the
9. One (1) crewmember may accompany two (2) inches height) at the rear of the clutch cover is fastened to the existing
driver to starting line. At Masters events, tunnel on both sides. belly pan, the area below the clutches
with the permission of the Race Director, (from front of cover to rear of cover and
two (2) mechanics are allowed on the ENGINE width of cover) must be covered with .090
starting line. 1. (Improved Stock, Pro Stock and Modified inch 6061T6 aluminum or equivalent. If
10. In qualifying rounds, drivers that “jump cover is .125 inch, 6061T6 aluminum or
start” will be disqualified. If Starter is classes) The following minimum standards equivalent steel material, belting is
unable to determine the jump starters, a for straight-thru silencers are required: recommended, but not mandatory. Clutch
restart will be held at the Starter’s a. Inner pipe must have at least 15 holes cover and related belting must be securely
discretion. In Final races, drivers that fastened.
“jump start” (“red light”) will be scored after per square inch. Minimum hole size
those who do not jump-start. 1/16 in. (Minimum 3/8 in. sound MODIFIED
11. A driver will be disqualified for changing absorbing material around the entire CLUTCH
lanes unless the driver is attempting to circumference of inner pipe). COVER
avoid an accident. The snowmobile may b. Inner pipe (perforated core) must
not leave the confines of the lane, run-off contact sound absorbing material (fiber bulkhead
area or the return lane. or steel wool packing). between engine
12. Snowmobile safety stands that catch and c. Outer pipe must be at least ¾ in. larger and clutches
retain track, traction component and other than inner pipe.
items that are thrown by a track are d. Minimum silencer length 3 in. 5. Backside of clutches must be covered by a
mandatory (see illustration in GENERAL portion of the clutch cover or by a
RULES AND REGULATIONS). The stand Fiber packing bulkhead of comparable material.
must be used whenever the rear of a
snowmobile is raised to clean out the Inner pipe 6. Aluminum brake disks not allowed.
engine or track.
13. Clean out will only be allowed at specified Outer pipe SKI SUSPENSION & STEERING
backboards. The snowmobile must be
placed on a safety stand and the safety DRIVE 1. Limiter straps may be used on all
stand must be against the clean-out 1. The snowmobile must be propelled by a suspensions in all classes.
backboard. Backboard minimum
requirements are eight (8) feet tall, four (4) variable ratio belt transmission. 2. All classes require a minimum amount of
feet horizontal space for each snowmobile. 2. (Improved Stock and Pro Stock) The suspension travel. See section for specific
Backboards must be sheeted with 3/4 inch required minimum.
plywood (no chipboard). Additional clean clutch cover must be separate of cowl
out boards may be placed in the paddock configuration and cover clutch perimeter 3. Suspension travel to be measured
area. and faces down to center of clutch bolt or vertically at the bumper. It is the driver’s
14. Cool down allowed in the hot pits for all below (see illustration). Cover must be and/or crew’s responsibility to demonstrate
classes. .090 inch 6061T6 aluminum or equivalent suspension travel.
15. Participant using external cooling system steel material and the outer perimeter be
must use a catch pan to stop any coolant covered with 6 inch belting. Other clutch 4. (Pro Stock and Modified classes) Spindle
from leaking onto ice/ground when in use cover materials not allowed. If 0.125 minimum wall thickness is 0.120 inch;
or being disconnected. aluminum or equivalent steel material is minimum outside diameter is 0.75 inch.
used, belting is recommended, but not Inspection hole required if wall thickness is
GENERAL SNOWMOBILE REQUIREMENTS required. Snowmobile with removable side not visible.
panels may bolt clutch cover to side panel
ADVANCING TO ANOTHER CLASS to meet this requirement. SKIS & SKI RUNNERS
1. Snowmobile moving to a class (other than IMPROVED STOCK 1. (Pro-Stock and Modified) It is highly
the class for which it qualifies) must meet and PRO STOCK recommended, if a cutting edge is used on
the criteria, safety and weight rules for that CLUTCH COVER a ski, that no more than five inches of
class (unless stated otherwise). ninety (90) degree cutting edge be used.
bulkhead
2. Snowmobile may be advanced to a higher between engine TRACK SUSPENSION
class and/or division without meeting and clutches
safety requirements for the higher class so 1. Improved Stock, Pro Stock and Modified:
long as the snowmobile advances All snowmobiles must use a device such
unchanged and remains compliant with all as stab wheels installed on the suspension
to prevent the slide rails from spearing the
track (see illustration).
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
STAB WHEELS equipped with foot pegs must also have 3. Drivers in the Stock classes must weigh a
(front of slide rails) running boards of tunnel like material. minimum of 180 pounds including
Running boards must be four (4) inches protective gear. If the driver does not
2. Dual suspension limiters are required in all wide and start one (1) inch behind the foot meet the weight requirement, ballast must
classes. In Stock and Improved Stock, pegs and extend forward along the tunnel be added to the snowmobile. Additional
track suspension limiters must be OEM to the rear of the clutch cover on both fuel and/or optional marginal snow wheels
type for the model or straps or chains. sides. added to the slide rails may be used as
OEM type screw adjusters for straps 4. Dulled foot traction devices allowed on the ballast.
allowed. running boards.
a. ON THE FLAT OF THE RUNNING 4. The snowmobile must meet the weight as
3. All classes require a minimum amount of filed by the manufacturer.
suspension travel. See section for specific BOARD - traction devices must be
required minimum. dulled and be no higher than 1/2 inch 5. Twenty (20) pounds will be added to the
above the flat of the running board. snowmobile weight (as filed by the mfr.)
4. Suspension travel to be measured b. ON TOP OF THE ROLLED EDGE - for fuel and studs.
vertically at the bumper. It is the driver’s traction devices must be dulled and be
and/or crew’s responsibility to demonstrate no higher than 1/4 inch above the top of NOTICE: Weights are reviewed annually.
suspension travel. the rolled edge of the running board.
c. The traction device may extend a 6. Stock alterations allowed in Oval Sprint
TRACK & TRACTION maximum of 1/4 inch beyond the side of racing for safety reasons are allowed.
the rolled edge for the purpose of
1. (Improved, Pro Stock and all Modified) mounting. There shall be no sharp 7. Commercially available gasolines that are
Track must be designated by the molder of edges to the side of the rolled edge.
the track for racing. It is recommended reformulated with up to 10% ethanol are
that the track be no more than 3 years old. STUTTER BOXES allowed in stock.
2. In Stock class, track width is as produced 1. No stutter boxes allowed unless otherwise ENGINE
for the model (unless a designated specified.
optional track of different width is used). 1. No component of the engine may be
In all other classes, there is no minimum IGNITION AND ELECTRICAL altered, changed, reduced or enlarged
track width. All tracks must be from the engine manufacturer’s original
commercially available. Track width must 1. The tether switch cord must be attached stock specifications, nor may any
remain as produced by the molder of the around the driver’s right wrist. The cord additional components be added to the
track. must be no more than 24 inches long engine. Blueprinting of engines is not
when fully extended (measured from the allowed. No removal of material
3. Tracks may not be reversed. switch to the driver’s wrist.) The tether whatsoever will be allowed. This is to
4. Track studs may be no more than 3/4 switch may be relocated. The tether include polishing, port matching,
switch may not be mounted to any moving deburring, glass or sand blasting surfaces
inches above the highest point of the track part of the steering mechanism. or material removal for the purpose of
or the traction lug. (See diagram in engine balancing or other reasons.
Appendix.) 2. Data acquisition and data acquisition
5. Studs must be placed between two track systems allowed. 2. Maximum cylinder overbore for wear
lugs and no more than 1.5 inches from cannot exceed .020 inches (1/2mm).
either lug. Penetration will be measured DRIVER RULES
from a straight line across the high point of 3. Replacement pistons must be stock OEM
the two lugs. 1. Neck bracing highly recommended in all for the model.
6. Except for under slide rails, all plates will classes. Neck bracing can be mandatory
be no greater than two and one quarter (2 at regional discretion. 4. There will be no more than one cylinder
1/4) inches in width and length. Plates base gasket to a cylinder. No changes in
welded onto track clips must be no longer VERIFICATION AND CONTROL engine dimensions can be made by gasket
or wider than track clip. Only one plate adjustments.
allowed per track clip. Only one traction 1. Mandatory teardown and inspection of first
point allowed per weld-on plate. Rubber place is required. Any other snowmobile 5. Spark plugs do not necessarily have to be
between ends of track clip may be (at the discretion of the Race/Tech OEM equipment in Stock classes.
trimmed to allow welding on stud plate. Director) may be torn down and inspected
7. Cleated tracks are not allowed. at Masters Drag events. Teardown is by 6. A maximum of one venturi per cylinder will
8. All tracks must be commercially available protest only at Amateur Drag events, or at be allowed in Stock classes. Any
from OEM or molder of track. Unless the discretion of the Race Director. exception must be approved in writing by
otherwise specified, no modifications or ISR.
changes allowed to track after production STOCK CLASSES AND RULES
by molder of the track. 7. OEM carburetor slide valve and
In stock and stock based classes, no change replacement jet components, without
FRAME & BODY or modification is allowed unless specifically modification, are allowed in all classes.
allowed by these rules. If these rules do not No modification to carburetor body will be
1. The maximum tunnel width will not exceed specifically allow a change or modification, allowed.
twenty (20) inches and the track must be then it must be assumed that the change or
confined within the width of the tunnel. modification is not allowed. 8. On snowmobiles with OEM electronic fuel
injection, commercially available electronic
2. Stock, Improved Stock and Pro Stock are STOCK SNOWMOBILE GENERAL control modules may be added to the
not allowed to use foot pegs, running REQUIREMENTS OEM ECU for the purpose of increasing or
board foot stops may be used and may not decreasing fuel delivery only. The added
be wider than the running board at the 1. The snowmobile must have original OEM module must be designed to plug directly
position they are installed and they may for the model engine, hood, frame, cowl, into the OEM ECU and/or the OEM wire
not extend higher than the top of the gas tank, carburetion, airbox, suspension harness without modification.
tunnel at the point of installation. and variable speed converter. Named
components must be OEM for the model NOTICE: This rule will be reviewed
3. (Modified Classes) Stirrups/pegs must be and year, or properly filed OEM
along side of the tunnel and may not replacement parts that supersede the annually.
extend above the tunnel or beyond the original OEM parts. Factory options are
rear of the tunnel. All snowmobiles not allowed. 9. On snowmobiles equipped with electronic
fuel injection, it is allowed to replace the
2. All snowmobiles must comply with the non-adjustable fuel pressure regulator with
GENERAL RULES AND REGULATIONS any commercially available, mechanically
SECTION. adjustable fuel pressure regulator.
(Unless OEM for the model, no
electronically controlled fuel pressure
regulators are allowed.) The regulator and
mechanical adjustment device must be
installed under the hood of the
snowmobile and not be accessible to the
driver while seated on the snowmobile.
10. Airbox may not be modified. Air box may
be removed. If removed, must be
replaced with commercially available
foam/paper/fabric air cleaners. Individual
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
air cleaners should be used on each 6. Radius rods may be located anywhere on 6. Any commercially available, one piece,
carburetor with suitable connecting the trailing arm where the manufacturer molded rubber track of the same length
adaptors if necessary. A redesigned ram has drilled or partially drilled for radius rod and width as OEM for the model track is
air box is not allowed. mounting holes. allowed. Modifications to install track are
11. No additional fuel pumps may be added to not allowed unless specified.
stock carbs. SKIS & SKI RUNNERS
12. Oil injection pump must remain in place FRAME & BODY
and remain functional. Lines may be 1. Aftermarket skis allowed. Skis must be
removed and plugged. Oil injector nozzles commercially available and marketed 1. Snowmobile width shall be as produced by
may be removed and holes may be through normal sales activity. Minimum the OEM manufacturer.
plugged. Premix gasoline may be used. aftermarket ski length must be 40 inches.
13. Engine must retain OEM for the model Ski width may not be trimmed. Skis may 2. Any chassis alterations, additions or
cooling system. not be interchanged between brands. removals, which alter stock appearances
14. On liquid cooled snowmobiles, except for Replacement ski must be the same or dimensions are not allowed.
quick disconnects and flow directional material as OEM ski for the model (i.e.
valves, the cooling circuits cannot be plastic to plastic, steel to steel). Lower ski 3. Tunnel can be repaired but must remain
modified or removed. Thermostats may surface must remain OEM material. OEM for the model length.
be removed. When the snowmobile is on
the course the cooling fluid must flow 2. Skis may be reinforced but must remain in 4. Windshield and windshield molding may
unobstructed throughout the entire cooling the original configuration. This reinforcing be removed.
system (no short circuiting). must be on the upper surface of the ski
15. OEM heat exchangers for the model only. 5. No additional venting allowed.
located under the tunnel may be relocated 6. Protective taping or screening will be
any place on the top, side or under the TRACK SUSPENSION
tunnel and must remain functional. restricted to the external openings only.
16. Harmonic balancer may not be removed. 1. The complete suspension must be used as
17. The complete OEM exhaust system must furnished and filed by the manufacturer. IGNITION & ELECTRICAL
be used as furnished and filed by the There will be no suspension options
manufacturer for the model. permitted in Stock classes. Track 1. Ignition must be OEM for the year and
suspension may be located anywhere in model.
DRIVE the tunnel where the manufacturer has
drilled, partially drilled or marked for 2. CDI module may be reprogrammed.
1. Any combination of springs, weights and mounting holes. Pre-drilled plates may be 3. Fixed ignitions may be advanced or
ramps may be used in the clutches. There drilled out to facilitate suspension
is no maximum clutch engagement RPM. adjustment. Pre-drilled backing plate retarded a maximum of 4°.
holes may not be enlarged or slotted. 4. No aftermarket device allowed which
2. No machining on clutches to
accommodate springs and weights. 2. Any steel or titanium suspension springs interrupts ignition for the purpose of launch
allowed. Torsion springs (not coil springs) control or traction control unless OEM for
3. No machining, grinding, cutting or welding may be shortened at the long end to the model.
allowed on clutches unless otherwise prevent contact with the track. OEM for 5. Lighting coil must remain in place.
specified. the model design concept must be 6. Stock snowmobiles will be allowed to add
maintained. or remove tachometers, speedometers, or
4. Metal may be removed but not added to heat gauges (openings must be closed).
primary clutch ramps or flyweights. 3. Must maintain two (2) inches of remaining 7. Electrical wiring must remain in place.
compression travel with driver on 8. Headlight and taillight must be OEM
5. Secondary clutch cams may be cut to any snowmobile. original equipment. Glass lenses must be
angle. Billet helixes allowed. taped over with transparent clear tape.
4. Marginal snow wheels and related Lights must remain in original mounting
6. No overdrive machining. hardware may be added to or removed location. Headlight and taillight must be
7. Drive belt need not be OEM for the model. from slide rails. Structural integrity must operational at the start of the race. Taillight
8. Any drive chain and sprockets may be be maintained. cannot be battery operate
9. Aftermarket sensors of any type can
used. 5. Rear axle idler wheels must remain OEM only be installed in the wye pipe or the
9. Track sprockets/drivers must remain for the model. OEM for the model rear exhaust canister.
idler wheels may be added to the rear axle.
OEM for the model.
10. Track drive sprockets may be changed 6. Shocks must remain OEM for the model
and remain in the OEM location. On
to use a 2.52 inch pitch designated R rebuildable shocks, spacers may be added
rated track. Sprockets must be OEM for internally to limit rebound travel, but not
the brand and of the same material and compression travel.
diameter (+/-0.5 inches) as the OEM
sprockets for the model. No machining 7. No device may be added that stops the
allowed to accommodate axle. suspension from going thru its normal
11. OEM for the model brake system including bottoming action.
master cylinder, caliper and disk, must
remain as produced by the OEM and must TRACK & TRACTION
be fully functional. No other brake
components may be added. 1. A track manufacturer (who has three step
distribution) may submit one track design
SKI SUSPENSION & STEERING with clip configurations to ISR Race Rules
Committee for approval. Approval will be
1. Any steel or titanium suspension springs based on the track manufacturer’s
adherence to rib/lug height, track
allowed. OEM for the model design durometer, track weight and other factors.
concept must be maintained. 2. No cutting, trimming or shaving of the track
or rubber studs/snow lugs allowed. The
2. Must maintain two (2) inches of remaining track must be used as produced by the
molder of the track. Acceptable traction
compression travel with driver on products allowed.
snowmobile. 3. Minimum lug height from the flat of the
track is 0.50 inch.
3. Shocks must remain OEM for the model
4. The track may not be reversed.
and remain in the OEM location. On 5. Track clips and guide clips may be
rebuildable shocks, spacers may be added replaced when worn. Guide clips may be
removed and replaced with track clips.
internally to limit rebound travel, but not Track clips may be removed and replaced
with guide clips. The track must retain the
compression travel. original number of clips with which it was
produced.
4. Handle bar extensions are allowed. All
ends must be plugged. (See diagram in
GENERAL RULES AND REGULATIONS
SECTION).
5. Handlebars with OEM mountain handles
may be replaced with any OEM handlebar
within the brand.
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
IMPROVED STOCK CLASSES AND RULES 2. Cylinders must be OEM for the model. 13. Oil pumps may be removed or disabled.
Must remain within OEM shell dimensions Oil tank must be removed. Oil injector
In stock and stock based classes, no to include crevices, bulges, etc. No visible nozzles may be removed and plugged. (If
change or modification is allowed unless external changes allowed even if the area oil tank and overflow tank are joined the oil
specifically allowed by these rules. If these is hidden by another part or bracket. tank must be disabled or the joined tanks
rules do not specifically allow a change or Number of cylinders must be OEM for the removed.)
modification, then it must be assumed that model. No external fastening devices
the change or modification is not allowed. allowed to secure or hold cylinders in 14. Flywheel / harmonic balancer may not be
1. There are six (6) Improved Stock classes place. removed.
offered at the promoter’s option at any 3. The cylinders may be raised to change 15. Torque arms allowed.
drag race. port height. If a plate is used to raise 16. Rigid motor mounts allowed. OEM for the
2. Snowmobile movement will be from Stock cylinder height, the plate, including
to Improved Stock. gaskets, cannot exceed 1/2 inch (0.50 model engine location must be
inch) in thickness. maintained. Replacing or adding metallic
CLASS MAX. CARBS MIN. engine mounts is not allowed. Replacing
CC COMB. 4. Engine may be bored up to class limit. A rubber/cushion parts with more rigid parts
Improved 440 OEM for WEIGHT one percent (1%) overbore allowed. is allowed.
Stock 500 the model 625 LBS (EXAMPLE: 670cc engine may be bored 17. Cooling systems must be operational.
440 600 OEM for up to 707cc’s and may not be bored up to May contain disconnects for cool down.
Improved the model 625 LBS 800cc’s to run in the 800cc class). Heat exchangers may be relocated,
Stock 700 OEM for modified or removed.
500 800 the model 700LBS 5. Crankshaft and crankcase must be OEM 18. Any functionally silenced exhaust system
Improved 1000 (645 for two for the model. OEM stroke must be allowed. A commercially available,
Stock OEM for cyl. engine) maintained. No modification allowed to functionally silenced muffler/silencer must
600 the model (Yamaha the external surfaces of the crankcase be installed and operational. (See General
RX-1 min. even if the area is hidden by another part Snowmobile Requirements in Drag Racing
Improved OEM for wt. 750 lbs.) or bracket. for details.)
Stock the model 750 LBS 19. Exhaust outlet must exit body downward
700 (695 for two 6. Cylinder head(s) must be OEM for the and rearward. (If OEM exhaust exits
Improved Any carb cyl. engine) model. The cylinder head may be behind driver, pipe need not go
Stock allowed 775 LBS modified internally including changing downward). The minimum combined
800 (685 for two replaceable combustion chambers and downward, rearward angle is 70° (from
Improved cyl. engine) machining out combustion chambers to centerline of crankshaft). Exhaust pipe
Stock 775 LBS use replaceable inserts. The visible, outer must not extend more than 3 in. beyond
1000 (685 for two portion of the cylinder head or cylinder chassis or body.
cyl. engine) head cover must remain stock appearing
and the spark plug must maintain OEM DRIVE
MINIMUM COMBINED WEIGHT IS THE location.
WEIGHT OF THE SNOWMOBILE AND 1. Any primary and secondary clutch may be
DRIVER. 7. Engine components allowable for used. Roller secondary clutches allowed.
modification or replacement.
NOTICE: Weights are reviewed annually. a. Bearings 2. Primary clutch and secondary clutch may
b. Rods (rod center to center must remain be modified (no RPM limit).
3. Any snowmobile may be reclassified and the same)
reassigned in the interest of fair c. Pistons 3. Jackshafts, of like material and weight,
competition. d. Piston pins may be changed to accommodate a clutch
e. Rings change. No welding allowed on a
4. Improved Stock snowmobiles may f. Gaskets jackshaft. Steel and chromoly allowed.
advance to higher displacement class and Titanium not allowed unless OEM for the
not be required to meet the minimum 8. Reeds and reed blocks may be changed, model. OEM location of shaft must be
weight for that higher class. (external plate may be thicker) if they do maintained.
not change the outside dimensions of the
GENERAL SNOWMOBILE REQUIREMENTS cylinder or crankcase. No external 4. Any track drive sprocket and non-driving
modifications may be made to the wheels allowed on the track drive axle.
1. Snowmobile must begin as a qualified crankcase or cylinder to accommodate Unless specified, no changes in drive,
stock snowmobile. All snowmobiles must reed block change. frame, or suspension allowed to accept
comply with GENERAL RULES AND track drive sprockets.
REGULATIONS SECTION. 9. Carburetors, flanges and intake manifold
must be OEM for the model. Internal 5. Track drive axle and chaincase must
2. Any alterations allowed in Stock are modifications are allowed. Carburetor remain OEM for the model and remain in
allowed in Improved Stock. throat may be bored. Intake concept and OEM location.
location must remain OEM for the model.
3. The snowmobile must have original OEM SKI SUSPENSION & STEERING
for the model engine, frame, suspension, 10. On snowmobiles with OEM for the model
fuel tank and seat. Named components Electronic Fuel Injection the throttle body, 1. Ski suspension and shocks must be OEM
must be OEM for the model and year, or including the exterior, may be modified for for the model and remain in OEM location.
properly filed OEM replacement parts that increased fuel flow. No welding of the
supersede the original OEM parts. throttle body allowed (not even for 2. Ski stance must be OEM for the model.
Factory options are not allowed. repairs). Systems that allow increased 3. Must maintain two (2) inches of remaining
fuel delivery may be used (i.e. Power
ENGINE Commander or others). The stock control compression travel with driver on
module must be used. No changes for snowmobile.
1. Engine components must be OEM for the increased airflow allowed. Increasing the 4. Handlebars with mountain handles may be
model unless otherwise specified. May be size of throttle body throat not allowed. replaced with any OEM handlebar within
modified internally, but engine must retain OEM for the model throttle plate (butterfly) the brand.
its complete external stock appearance must be used without modification.
and dimensions. Parts identification SKIS & SKI RUNNERS
numbers must not be removed. 11. Except as noted, additional fuel delivery
system or pressure charging is not allowed. 1. Aftermarket skis allowed. Skis must be
commercially available and marketed
12. Internal and external modifications may be through normal sales activity. Minimum
made to the airbox. Airbox may be aftermarket ski length must be 40 inches.
removed. Air filters may be used. Ski width may not be trimmed. Skis may
not be interchanged between brands.
Lower ski surface must remain OEM.
TRACK SUSPENSION
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
1. OEM for the model suspension must be 5. A pony pac ignition system may be In stock and stock based classes, no change
used. Suspension may be moved up and installed on four cylinder, 2-stroke Yamaha or modification is allowed unless specifically
down in the tunnel (limit 3 inches). OEM engines, allowing a change in the firing allowed by these rules. If these rules do not
location must be maintained and may not order to one hundred eighty (180) specifically allow a change or modification,
protrude beyond tunnel configuration. degrees. then it must be assumed that the change or
modification is not allowed.
2. Must maintain two (2) inches of downward 6. Tachometers, speedometers and/or heat
compression travel with driver on gauges may be added or removed. There are five (5) Pro Stock classes:
snowmobile.
7. Open instrument holes must be closed. CLASS MAX.CC MINIMUM
3. Shocks must be OEM for the model and 8. Electrical wires/wire harnesses and COMBINED
remain in OEM location. Pro Stock 500 500 WT.
instrument drive cables may be removed. Pro Stock 600 600 550 Ibs.
4. Any size, material, and number of rear 9. Headlight assembly may be removed 625 Ibs.
axle idler wheels allowed. Unless Pro Stock 700 700 (550 for two
specified, no modification to chassis or (opening must be closed). Headlight cyl. engine)
suspension allowed to accept idler wheels. consoles are not considered part of Pro Stock 800 800 625 Ibs.
Rear axle may be moved upward in the headlight assembly. (550 for two
slide rails to accept larger rear idler Pro Stock 1000 1000 cyl. engine)
wheels. IMPROVED STOCK 1000 RULES 625 Ibs.
(550 for two
5. Commercially available long track rails 1. Minimum combined (driver and cyl. engine)
and rail extensions allowed. To snowmobile) weight is seven hundred 625 lbs.
facilitate installation of long track rails, seventy five (775) pounds. (550 for two
suspension may be moved up or down cyl. engine)
in the tunnel (a limit of three inches). ENGINE
The front torque arm must be OEM MINIMUM COMBINED WEIGHT IS THE
stock and located in the stock location 1. Any stock qualified model may be used WEIGHT OF THE SNOWMOBILE AND
on the slide rail. Rear torque arm must and the engine may be bored up to class DRIVER.
remain OEM stock for the model and limit. A one (1) percent over class cc
may be relocated to accommodate the allowed (1010 cc). NOTICE: Weights are reviewed annually.
longer track and rail assembly.
Suspension components must remain 2. Rod center to center may be changed. GENERAL
OEM stock for the model. Tunnel must 3. Stroke may be changed.
be extended to accommodate the 4. Crankshaft may be modified or replaced. 1. Pro Stock snowmobiles must originate as
longer track and suspension. An 5. Crankshaft gears may be changed. ISR stock qualified snowmobiles.
approved tunnel enclosure must be 6. Cylinders may be modified but must retain
added. 2. OEM serial numbers are not required, but
complete OEM dimensions to include engine and frame must have unique
TRACK & TRACTION crevices, bulges, etc. If an OEM cylinder is identification numbers that identify the
modified it must remain within .020 inches OEM model and year.
1. Any commercially available one-piece (1/2mm) per side, .040 inches (1mm)
molded rubber track allowed. Track must overall of the OEM cylinder outer shell 3. The OEM for the model frame, engine,
be race designated by the molder of the dimensions. Modifications must be seat and fuel tank must be used. Unless
track. No cleated tracks allowed. Unless blended into original castings to retain otherwise specified, all parts and
specified, no modification to drive, frame OEM appearance. components including the hood, seat,
or suspension allowed to install track. 7. Any aftermarket cylinder is allowed. engine, drive and chassis must retain
Aftermarket cylinders must be OEM stock appearance for the model.
2. Commercially available long track rails commercially available. The outside of an
and rail extensions allowed. aftermarket cylinder may not be modified. 4. The OEM for the model frame including
8. Cylinders may not be interchanged bulkhead and tunnel must be used as
3 Track must remain untouched (no between brands. Welding on crankcase is structural members to mount the engine,
trimming). not an acceptable method to adapt drive components and suspension.
aftermarket or other OEM cylinders to
4. Minimum lug height is 0.500 inches. crankcase. 5. An OEM for the brand “like chassis” may
5. Snowmobile must maintain a minimum of 9. Any commercially available cylinder head be substituted for the OEM chassis. “Like
allowed. chassis” must have the same front
twenty (20) inches of track length on the 10. Intake concept and location must remain suspension concept as the original chassis
course surface when snowmobile is under OEM for the model. (i.e. trailing arm, “A” arm, or strut). When
full power. 11. The reed valve mounting area on the engine is installed in the “like chassis”, the
crankcase may be modified to change crankshaft must be located in the OEM
FRAME & BODY reed angle. The upper surface of the location for the chassis. The engine
intake tract may be reinforced by welding installation must conform to the engine
1. Any chassis alterations, additions or or bonding. location rules.
removals, which alter stock appearance or 12. More than one OEM type fuel pump
dimensions are not allowed. Tunnel can be allowed. 6. Any snowmobile may be reclassified in the
repaired but must maintain OEM length. 13. Carburetors, mounting spigots and air interest of fair competition.
boots may be modified or replaced. Flange
2. The OEM fuel tank must be the only tank can be modified internally. 7. Snowmobile must comply with GENERAL
that can be used for fuel supply. Oil 14. Airbox may be removed. RULES AND REGULATIONS SECTION.
injection tanks may not be used as a fuel
tank. TRACK & TRACTION 8. Any alterations allowed in Stock and
Improved Stock classes are also allowed.
3. Removal of any insulation that alters the 1. Commercially available long track kits
outside stock appearance is not allowed. allowed. Kit must be used in its entirety. ENGINE
4. Any hood or side panels that maintain IGNITION & ELECTRICAL 1. Crankcase, cylinders and crankshaft must
stock appearance (as defined) for the be from the same stock qualified model.
make and model may be used. 1. Any ignition may be used. Electrical Must retain original number of cylinders.
stutter boxes, launch control and traction
IGNITION & ELECTRICAL control allowed. 2. Crankcase may be modified internally
provided the engine retains its complete
1. Ignition must be OEM for the model. PRO STOCK CLASSES AND RULES
2. Fixed ignitions may be moved (+ or -) four
(4) degrees.
3. No aftermarket device allowed which
interrupts ignition for the purpose of launch
control or traction control unless OEM for
the model.
4. Lighting coil must remain in place.
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
external stock appearance and dimensions belly pan and must be within 1/4 inch of joints, tie rods, linkages, IFS trailing arms
except as noted in these rules. the belly pan. Maximum opening in belly and radius rods must remain OEM design
3. The only external modification allowed to pan is one hundred (100) square inches. concept but may be changed in shape and
the crankcase is to the cylinder mounting Radiator must be functional. appearance. Must remain in the OEM
surface and must be covered by the OEM 14. Any functionally silenced exhaust system location on the chassis.
for the engine cylinder base gasket. allowed. Exhaust outlet must not protrude 2. Sway bar and links may be removed. If
4. Crankshaft must be OEM for the model. more than three (3) inches beyond the sway bar is disconnected, it must be
a. Crankshaft may be modified. chassis or hood configuration. A removed.
b. Stroke may be changed. Connecting commercially available, functionally 3. Material substitution is allowed. Replaced
silenced muffler/silencer must be installed components must be as strong or stronger
rod length may be changed. and operational. (See General than OEM components.
c. Four cylinder crankshaft gears may be Snowmobile Requirements in Drag Racing 4. Shock absorbers may be replaced. Only
for details.) commercially available, hydraulically
changed with any OEM crankshaft gear. 15. Exhaust outlet must exit body downward damped shocks specified for use on full-
5. Cylinders must be OEM for the model and and rearward. (If OEM exhaust exits sized snowmobile are allowed. Must
behind driver, pipe need not go remain in OEM location on the chassis.
mounted in OEM location and orientation. downward). The minimum combined 5. Spindles may be strengthened or replaced
a. Cylinder may be modified internally downward, rearward angle is 70° (from with a stronger spindle. Spindle height
centerline of crankshaft). Exhaust pipe must remain within 10% of the original
provided the engine retains its complete must not extend more than 3 in. beyond OEM dimensions.
external stock appearance and chassis or body. 6. Minimum ski stance (center to center of
dimensions except as noted in these the ski runners) is 40 inches.
rules. DRIVE 7. Ski widening devices allowed. No
b. Cylinder overbore is limited to a 2% maximum ski stance width.
increase in displacement over the cc 1. Any primary or secondary clutches are 8. Handlebars, handlebar grips and controls
limit for the class. allowed. may be modified.
c. Cylinder may be bored up or sleeved 9. Must be a minimum of 2 inches of
down. 2. Clutch jackshaft may be changed or remaining compression travel with driver
d. OEM cylinder outer shell dimensions modified (no welding on jackshaft). on snowmobile. (See FRAME & BODY for
modification must be within .020 inches minimum ground clearance rules.)
(1/2mm) per side/.040 inches (1mm) 3. Relocation of crankshaft, jackshaft and
overall of the OEM cylinder dimensions. track drive axle allowed. Relocation may SKIS & SKI RUNNERS
Modification must be blended into be in any direction that is perpendicular to
original casting to retain OEM crankshaft. The relocation distance of the 1. Any commercially available OEM
appearance. three shafts combined cannot exceed 1.0 appearing or aftermarket ski may be used
e. Cylinder height may be modified to inch. One of the three shafts may be provided the original spring concept
change port height. If a plate is used to moved 1 inch or two or three of the shafts remains the same.
raise cylinder height, the plate, including may be moved but limited to a total
gaskets, cannot exceed 1/2 (.500) inch. combined distance of 1.0 inch. (The 2. Minimum ski length is twenty (20) inches.
6. Any carburetor may be used. Only one distances that the shafts are moved must
venturi allowed per cylinder. be added together and the sum total must TRACK SUSPENSION
a. Intake concept and location must not exceed 1.0 inch.)
remain OEM for the model. 1. Any track suspension allowed that can be
b. Fuel injection not allowed unless OEM 4. Any track drive sprocket and non-driving installed within the confines of the tunnel.
for the model engine. wheels allowed on the track drive axle.
c. No turbo-chargers, super-chargers or Unless specified, no changes in drive, 2. Material substitution is allowed. Replaced
nitrous allowed. frame, or suspension allowed to accept components must be as strong or stronger
7. Intake concept and location must remain track drive sprockets. than OEM components.
OEM for the model engine with the
exception that EFI models may be 5. Drive reduction system must be OEM for 3. Shock absorbers may be replaced. Only
changed to carburetor induction. the model concept (i.e. chain, belt, or commercially available, hydraulically
8. Reeds and reed cage may be replaced or gear). Chain case / gear case and cover damped shocks specified for use on a
modified so long as the outside may be from any stock qualified model snowmobile are allowed.
dimensions of the cylinder or crankcase within the brand.
are not compromised. External plate may a. Chain case / gear case modification is 4. Outboard mounted shocks do not
be thicker. No welding or bonding to not allowed. Chain case / gear case compromise OEM stock appearance.
cylinder or crankcase to accommodate must be functionally driving the
reed assembly allowed. Reed assembly snowmobile with the OEM for the model 5. Must be a minimum of 2 inches of
changes must be accomplished by bolting drive concept (i.e. chain, belt or gear). remaining compression travel with driver
only. b. Any chain, belt, sprockets, and gears on snowmobile. (See FRAME & BODY for
9. Other engine components allowable for allowed for drive reduction system. No minimum ground clearance rules.)
modification or replacement: modification allowed to chaincase for
a. Cylinder heads installation of these parts. 6. Commercially available long track kits
b. Bearings allowed. Kit must be used in its entirety.
c. Rods 6. Brake assembly may be on either the
d. Pistons, pins and rings jackshaft or the track drive axle. TRACK & TRACTION
e. Gaskets
f. Bolt-on intake and exhaust flanges 7. Brake caliper may be either dual opposing 1. Any commercially available one-piece
g. Fuel pump piston or single piston type. molded rubber track allowed. Track must
h. Engine mounts be race designated by the molder of the
10. Airboxes may be removed. 8. Minimum brake disk diameter is 7.0 track. No cleated tracks allowed.
11. Engine must retain original cooling inches. (If brake disk is mounted to track
concept. (Liquid, fan or free-air cooling drive axle and a dual opposing piston 2. Track and track suspension must fit within
must be retained but cooling circuits can caliper is used, the disk minimum diameter the confines of the tunnel. Snowmobile
be modified or removed.) is 6 inches.) must maintain twenty (20) inches of track
12. Water pumps may be removed. length on the course surface when the
13. Radiators and ducting may be used but 9. Pro Stock qualified snowmobiles need not snowmobile is under full power.
must not change OEM appearance. comply with Modified brake requirements
Radiator must not protrude beyond the when jumping up into Modified classes. 3. Track lug height may be trimmed to a
minimum of ½ inch lug height. No other
SKI SUSPENSION & STEERING track trimming allowed.
1. Front suspension components including 4. Holes for traction products must be a
struts, arms, spindles, rod ends, spherical minimum distance of 5/8 inch from track
edge or any other hole or opening in the
track. A maximum of 2 holes allowed in
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
each track segment outside of each slide PRO STOCK 1000 RULES TURBO RESTRICTOR PLATE
rail. A maximum of 4 holes allowed in
each track segment inside the slide rails. GENERAL Exhaust gas in
(A total of 8 holes per track segment.)
1. Minimum combined weight of snowmobile, Required
FRAME & BODY fuel, driver and driver gear is 625 lbs. restrictor plate
1. The OEM for the model frame including ENGINE Fresh air in Exhaust
bulkhead and tunnel must be used as gas out
structural members to mount the engine, 1. Aftermarket cylinders for the brand are
drive components and suspension allowed. Air to engine
components.
2. Cylinders must be commercially available. ENGINE
2. Chassis reinforcement allowed. No 3. Cylinders may not be interchanged
lightening holes can be drilled that alter 1. The engine must have been manufactured
the outside appearance for the model. between brands. Welding or bonding on a for snowmobile use (this does not include
crankcase is not an acceptable method to outboard, motorcycle, aircraft or
3. Structural integrity must be maintained. adapt aftermarket cylinders. automotive engines, etc.). The Race Rules
Replaced components must be as strong 4. Any commercially available cylinder head Committee will approve the validity of all
or stronger than OEM components. The allowed. engines. Watercraft crankcase and
Race / Tech Director shall have the 5. The reed valve mounting area on the crankshaft from a snowmobile
authority to determine structural integrity. crankcase may be modified to change manufacturer may be used.
reed angle. The upper surface of the
4. Access openings for component Intake tract may be reinforced by welding 2. Cylinder maximum overbore is limited to
accessibility will be allowed, but must be or bonding. two (2) percent over the cc displacement
closed with original type materials, i.e., for the class.
hinged clutch covers. IGNITION & ELECTRICAL
3. Open modified 1000 maximum overbore is
5. Frame must have a sheet of metal the 1. Any ignition may be used. Electrical limited to five (5) percent over the cc
same thickness as the tunnel permanently stutter boxes, launch control and traction displacement for the class.
fastened to the topside or underside of the control allowed.
tunnel. The sheet of metal shall be the 4. No super charging, turbo charging allowed
same width as the tunnel and shall extend OPEN MOD CLASSES AND RULES unless otherwise specified.
from the rear of the tunnel to the bulkhead.
There are five (5) Open Modified classes: 5. Fuel injection allowed.
6. Hood to belly pan molding must remain 6. Exhaust not enclosed within the confines
intact. The molding may be lightened as CLASS MAXIMUM CC
long as it does not alter the outside OEM Open Mod 500 500 of the cowl must point rearward,
appearance. Open Mod 600 600 downward and extend rearward beyond
Open Mod 700 700 front cross member/spindle centerline.
7. Seat must remain in OEM contour and be Open Mod 800 800 Exhaust system cannot compromise or
stock appearing. Seat may be lowered Open Mod 1000 1000 exceed overall snowmobile length and
equally front to rear, but must be at least width.
six (6) inches thick (or OEM height if less GENERAL 7. Exhaust system must be functionally
than 6 inches) at its minimum dimension silenced. (See General Snowmobile
(seat height will be measured from the top 1. Competition is open to any snowmobile, Requirements in Drag Racing for details.)
of original tunnel to top of seat in rider less either production or one of a kind 8. Exhaust system must fit within overall
state. Measurements will be made at the experimental (which could include rear maximum length and width rules.
lowest point of the seat. The rigid console engine type snowmobiles).
cover may be lowered to blend into seat DRIVE
contour. 2. Minimum wet weight (without gas) is two
hundred fifty (250) pounds. 1. Modified 800cc classes and above must
8. The outside gas tank shell must remain have a twin opposed piston caliper braking
intact and in its OEM location. The fuel 3. 800cc and 1000 cc - maximum overall system with a minimum 3/16 (.015 inch
tank may be modified to accommodate a length 144 inches. tolerance) inch thick, 7.0 inch minimum
fuel cell. The fuel cap may be replaced diameter brake disc, mounted on the drive
with the fuel cell cap. All fuel must be 4. All snowmobiles competing in Open axle. Any manufactured brake disc may
contained in the OEM for the model fuel Modified Class must comply with be milled or drilled in the original pad
tank location. The use of a fuel cell used GENERAL RULES AND REGULATIONS contact area (all pads inclusive). The disc
within the above rule will not compromise SECTION. pad contact area may not be reduced
OEM appearance. more than 15% of the original pad contact
5. The Race Director shall have the authority area.
9. Front air dams allowed. Must be a to determine structural integrity.
minimum of 2 inches above the ground SKI SUSPENSION AND STEERING
with front suspension totally compressed. 6. 4-stroke powered snowmobiles in the
1000cc class may incorporate a 1. Must be a minimum of 2 inches of
10. Except for front air dam (which requires 2 turbocharger with these restrictions: remaining compression travel with driver
inch clearance), all other parts and a. A ¼ inch thick restrictor plate before on snowmobile.
components must maintain a minimum of the turbo fresh air intake is required.
1 inch ground clearance with the Maximum bore size 60 mm, bore must 2. Minimum ski stance (center to center of
suspension fully compressed. be straight with no taper or chamfer. the ski runners) is 40 inches. No
b. OEM for the model engine cylinder maximum ski stance width. Snowmobiles
IGNITION & ELECTRICAL head (internal modifications allowed). built before 1 Jan 06 are exempt.
1. Any ignition allowed. (Stutter boxes and c. Air to air intercooler only, no water
injection. 3. Ski suspension must have at least one
other ignition devices allowed.) d. Minimum combined weight of 625 lbs. hydraulic shock absorber on each side.
2. Any instrumentation allowed. Tachometer, e. Identification tags and stampings on Snowmobiles built before 1 Jan 06 are
turbochargers must remain intact as exempt.
speedometer or heat gauges may be purchased.
added or removed. Open instrument holes TRACK SUSPENSION
must be closed.
3. Electrical wiring may be removed.
4. Headlight assembly may be removed
(opening must be closed). Headlight
consoles are not considered part of
headlight assembly.
5. Aftermarket sensors of any type can
only be installed in the wye pipe or the
exhaust canister.
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
1. Must be a minimum of 2 inches of 8. Fuel injection not allowed unless OEM for PRO MAX
remaining compression travel with driver the model.
on snowmobile. Pro-Max is a class designed to allow
9. EFI models may be changed to carburetor competition between extremely high
TRACK & TRACTION induction. horsepower sleds in various chassis designs.
1. Any commercially available one-piece 10. Exhaust not enclosed within the confines The class is limited to 140 miles per hour
molded rubber track allowed. Track must of the cowl must point rearward and maximum. Whenever 140 miles per hour is
be race designated by the molder of the downward and extend beyond front cross reached, the race course will be shortened by
track. No cleated tracks allowed. member/spindle centerline. Exhaust 25 feet. ISR will advise all affiliations by
systems cannot compromise/exceed bulletin when this threshold is reached, and
2. Track lug height may be trimmed to a overall snowmobile length and width. will specify the new track length limitation.
minimum of ½ inch lug height. No other Exhaust stinger must be directed
track trimming allowed. downward and rearward. Maximum initial course length is specified as
660 feet for Ice and Snow drags, and 500 feet
3. Minimum track width is 13.5 inches. 11. Exhaust system must be functionally for Grass and Dirt drags.
4. Track must maintain twenty (20) linear silenced. (See General Snowmobile
Requirements in Drag Racing for details.) All rules for this class are subject to change at
inches of length on the course surface anytime and without any grace period.
when the snowmobile is under full power. 12. Exhaust system must fit within overall
maximum length and width rules. GENERAL
FRAME & BODY
SKI SUSPENSION AND STEERING 1. All snowmobiles competing in the Pro Max
1. Must have sheet metal the same thickness class must comply with GENERAL RULES
as the tunnel material permanently 1. Must be a minimum of 2 inches of AND REGULATIONS SECTION.
fastened to the top or bottom side of the remaining compression travel with driver
upper tunnel surface. The sheet metal on snowmobile. 2. Race Director shall have the authority to
must be the same width as the tunnel and determine structural integrity.
must extend from the rear of the tunnel to 2. Ski suspension must have at least one
the horizontal centerline of the track drive hydraulic shock absorber on each side. 3. Competition is open to any snowmobile,
axle. Tunnels 1/8 inch (.125) thick or either production or one of a kind
thicker do not require this added sheet SKIS & SKI RUNNERS experimental units, (which could include
provided that the 1/8 inch (.125) tunnel rear engine type units).
extends to the horizontal centerline of the 1. Any commercially available OEM
track drive axle. appearing or aftermarket ski may be used 4. Minimum wet weight (without gas) is six
provided the original spring concept hundred and twenty five (625) pounds.
2. A skid plate (belly pan) is required. remains the same.
5. Maximum overall length is 144 inches.
PRO MOD RULES 2. Minimum ski length is twenty (20) inches.
(formerly FACTORY MOD) ENGINE
TRACK SUSPENSION
1. There are two (2) Pro Mod Classes: 1. The engine must have been
1. Must be a minimum of 2 inches of manufactured for snowmobile use (this
Classes and Max CC. Weight remaining compression travel with driver does not include outboard, motorcycle,
Pro Mod 800 625 lbs on snowmobile. aircraft or automotive engines, etc.). The
Pro Mod 1000 625 lbs TRACK & TRACTION Race Rules Committee will approve the
validity of all engines. Watercraft
MINIMUM COMBINED WEIGHT IS THE 1. Any commercially available one-piece crankcase and crankshaft from a
WEIGHT OF THE SNOWMOBILE AND molded rubber track allowed. Track must snowmobile manufacturer may be used.
DRIVER. be race designated by the molder of the
track. No cleated tracks allowed. 2. There is a 2000 maximum c.c. limit on total
GENERAL engine volume.
2. Track lug height may be trimmed to a
1. All snowmobiles competing in the Pro Mod minimum of ½ inch lug height. No other 3. One power adder, allowed. Supercharging,
class must comply with GENERAL RULES track trimming allowed. turbo charging, or nitrous oxide systems are
AND REGULATIONS SECTION. allowed, but may not be combined.
3. Minimum track width is 13.5 inches. Example, if a competitor adds a
2. Race Director shall have the authority to 4. Snowmobile must maintain twenty (20) turbocharger to an engine, he may not also
determine structural integrity. add a nitrous system.
linear inches of track length on the course
3. The snowmobile must be Stock Appearing surface when the snowmobile is under full 4. Fuel injection systems are allowed.
and have a unique identification number. power. 5. Exhaust not enclosed within the confines of
ENGINE FRAME & BODY the cowl must point rearward and
downward and extend beyond front cross
1. The engine must be from a stock qualified 1. All Pro Mod snowmobiles will have a sheet member/spindle centerline. Exhaust
snowmobile. (1000cc class only, of metal the same thickness as the tunnel systems cannot compromise/exceed overall
aftermarket cylinders allowed.) material permanently fastened to the top snowmobile length and width. Exhaust
or bottom side of the upper tunnel surface. stinger must be directed downward and
2. Cylinder maximum overbore is limited to The sheet of metal shall be the same rearward.
two (2) percent over the cc displacement width as the tunnel and shall extend from 6. Exhaust system must be functionally
for the class. the rear of the tunnel to the horizontal silenced. (See General Snowmobile
centerline of the track drive axle. Tunnels Requirements in Drag Racing for details.)
3. Cylinder, crankcase, crankshaft and heads 1/8 inch (.125) thick or thicker do not 7. Exhaust system must fit within overall
may be interchanged within the brand. require this added sheet provided that the maximum length and width rules.
Watercraft crankcase and crankshaft from 1/8 inch (.125) tunnel extends to the
a snowmobile manufacturer may be used horizontal centerline of the track drive DRIVE
axle.
4. Welding on the crankcase allowed. 1. Any CVT type primary and secondary clutch
5. Induction concept and location must 2. Hood must have top and side cowling and may be used.
must contain at least one thousand three
remain OEM for the model. hundred (1300) square inches. 2. Primary clutch and secondary clutch may
6. Any carburetor may be used. Only one be modified (no RPM limit)
3. A skid plate (belly pan) is required.
venturi allowed per cylinder. 4. Front air dams allowed. Must be a 3. Clutch cover must have full facial coverage
7. No super charging, turbo charging or and 360-degree elliptical coverage in the
minimum of 2 inches above the ground direction of clutch/belt travel (see
nitrous allowed. with front suspension fully illustration). Clutch cover must be .090 inch
compressed. 6061T6 aluminum or equivalent steel
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
material and be covered with six (6) inch 5. Snowmobile must maintain twenty (20) Mountain Modified OPEN
belting. Other clutch cover materials not linear inches of track length on the course
allowed. If the clutch cover is fastened to surface when the snowmobile is under full MOUNTAIN SPECIALTY CLASSES
the existing belly pan, the area below the power.
clutches (from front of cover to rear of cover Mountain Stock 600S (single pipe)
and width of cover) must be covered with 6. Traction screws may be used in the track Mountain Stock 700S (single pipe)
.090 inch 6061T6 aluminum or equivalent. lugs. Must be installed parallel to the track Mountain Stock 800S (single pipe)
If cover is .125 inch, 6061T6 aluminum or lug. Installed screws must not compromise
equivalent steel material, belting is the structural integrity of the track. Screws MOUNTAIN SLED GENERAL RULES
recommended, but not mandatory. Clutch must be installed completely into the track
cover and related belting must be securely lug, and the shoulder of the screw must fully 1. All rules and safety requirements from
fastened. contact the lug. The traction screw cannot Drag Racing and from General Rules and
touch or enter the fiberglass rod. Screws Regulations apply unless otherwise stated.
MODIFIED must be .250 shorter than the lug height.
CLUTCH 2. If it isn’t stated in the book that it can be
COVER 7. Any traction device must not extend more done, consider that it cannot be done.
than ¾ inch, (.750 inch) above the highest
bulkhead point of the track or traction lug. 3. Unless otherwise noted, minimum traction
between engine rib height is 1.4 inches for all tracks in all
and clutches FRAME & BODY classes.
4. Backside of clutches must be covered by a 1. All Pro Max snowmobiles will have a sheet TRACK AND TRACTION (ALL CLASSES)
portion of the clutch cover or by a bulkhead of metal the same thickness as the tunnel
of comparable material. material permanently fastened to the top or 1. Traction screws may be used in the track
bottom side of the upper tunnel surface. lugs. Must be installed parallel to the track
5. Pro Max class sleds must have a twin The sheet of metal shall be the same width lug. Must not compromise the structural
opposed piston caliper braking system with as the tunnel and shall extend from the rear integrity of the track. Must be screwed
a minimum 3/16 (.015 inch tolerance) inch of the tunnel to the horizontal centerline of completely into track lug. Shoulder must
thick, 7.0 inch minimum diameter brake the track drive axle. Tunnels 1/8 inch (.125) contact track lug.
disc, mounted on the drive axle. Any thick or thicker do not require this added
manufactured brake disc allowed, except no sheet provided that the 1/8 inch (.125) 2. Studs may be used. Maximum 2 per track
aluminum brake disc may be used. tunnel extends to the horizontal centerline segment. Must meet Snow Cross rules for
of the track drive axle. length and height. Drilling or cutting of
SKI SUSPENSION AND STEERING holes in track is not allowed except to
1. Must be a minimum of 2 inches of 2. Hood must have top and side cowling and mount traction devices
must contain at least one thousand three
remaining compression travel with driver on hundred (1300) square inches. 3. Maximum hole size is 5/16 inch.
snowmobile.
2. Ski suspension must have at least one 3. A skid plate (belly pan) is required. MOUNTAIN STOCK RULES
hydraulic shock absorber on each side.
Snowmobiles built before Jan 09, are exempt IGNITION & ELECTRICAL ENGINE
until 2010. 1. Airbox may be removed. If removed, must
3. Minimum ski stance (center to center of ski 1. Any ignition may be used. Electrical
runners) is 40 inches. stutter boxes, launch control and be replaced with a commercially available
traction control allowed. foam/paper type filter. Airbox may not be
SKIS & SKI RUNNERS modified.
MOUNTAIN SNOWMOBILE DRAG
1. Any commercially available OEM appearing RACING CLASSES AND RULES SKI SUSPENSION AND STEERING
or aftermarket ski may be used provided the
original spring concept remains the same. The following Mountain Snowmobile Drag 1. No tie down or stop devices to reduce
Racing Rules apply to ISR Drag Racing suspension travel allowed. Suspension
2. Minimum ski length is twenty (20) inches events that feature snowmobiles with must maintain full OEM travel for the
on dirt, grass or ice drag racing, and ( 40) tracks of at least 141 inches in length. The model.
inches on snow drag racing. format may vary according to region and
TRACK SUSPENSION promoter preference. All such variations TRACK SUSPENSION
should be advertised for the information
1. Must be a minimum of 2 inches of and convenience of competitors. 1. No tie down devices to reduce suspension
remaining compression travel with driver on travel allowed. Suspension must maintain
snowmobile. MOUNTAIN STOCK CLASSES full OEM travel for the model.
TRACK & TRACTION
Mountain Stock 500 TRACK AND TRACTION
1. Any commercially available one-piece Mountain Stock 600
molded rubber track allowed. Track must Mountain Stock 700 1. Minimum lug height of track is 1.4 inch
be race designated by the molder of the Mountain Stock 800 unless OEM track for the model has
track. No cleated tracks allowed. Mountain Stock 1000 shorter lugs.
2. Speed tracks and suspensions will be MOUNTAIN IMPROVED STOCK CLASSES 2. Any commercially available one-piece
allowed. molded rubber track of OEM for the model
Mountain Improved Stock 500 length may be used. No chassis or drive
3. Track lug height may be trimmed to a Mountain Improved Stock 600 modifications allowed to install track
minimum of ½ inch lug height. No other Mountain Improved Stock 700 unless specified.
track trimming allowed. Mountain Improved Stock 800
Mountain Improved Stock 1000 3. No track trimming allowed except to clear
4. Minimum track width is 13.5 inches. heat exchangers.
MOUNTAIN MODIFIED CLASSES
4. Commercially available long track kits
Mountain Modified 500 allowed. The long track alteration kit must
Mountain Modified 600 be used in its entirety.
Mountain Modified 700
Mountain Modified 800 5. No traction devices may be added to the
Mountain Modified 1000 track.
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
MOUNTAIN IMPROVED ENGINE King of the Hill
STOCK RULES King of the Hill (Non-Aspirated)
1. Modified OPEN only - turbo charging or
nitrous oxide is allowed. HILL DRAG FORMAT
IMPROVED STOCK WEIGHT 2. Exhaust systems must be functionally The following rules govern the conduct of
silenced. ISR Hill Drag events. The format may vary
1. The snowmobile must meet the weight as according to the region, hill conditions and
filed by the manufacturer for the year and SKI AND SKI RUNNER promoters preference. Any and all
model. variations need to be advertised for the
1. Any commercially available ski allowed. information and convenience of
2. 20 pounds will be added to the filed weight Minimum length 38 inches. competitors. Alternate formats will be
for fuel and traction products. allowed at the discretion of the ISR affiliate
TRACK SUSPENSION with the pre-approval of ISR. The alternate
3. Minimum driver weight (with driver gear) is format cannot contradict the basic format
180 pounds. Ballast may be added to the 1. Any suspension is allowed. Must have 6 for hill drag competition.
snowmobile to meet this requirement. inches of freestanding downward travel at
the rear bumper. Order of Event
ENGINE The order of classes to be run in an event will
2. No tie down devices to reduce suspension be determined by the promoter. They will be
1. Commercially available aftermarket travel to less than 6 inches allowed. posted prior to the start of the event.
cylinder heads are allowed.
FRAME AND BODY Driver Point System
SKI SUSPENSION AND STEERING 1. Hill drag circuits may formulate a point
1. The fuel tank must be from a stock
1. No tie down devices to reduce suspension qualified snowmobile. Fuel must be system at their discretion.
travel allowed. Suspension must maintain contained in the fuel tank only. 2. Suggest point system is as follows.
full OEM travel for the model.
2. Tunnel material in all snowmobiles in all Finish Points per Ex. Based on
2. Commercially available aftermarket classes must maintain its structural
suspension parts are allowed. integrity. position entry 30 enties
TRACK SUSPENSION 3. The hood must have top and side cowling 1 5 5x30=150
and must contain at least one thousand
1. Any commercially available track three hundred (1300) square inches. (To 2 4 4x30=120
suspension parts allowed. Unless receive any contingencies, hood must be
otherwise specified, modifications to install identifiable as an OEM style hood and 3 3 3x30=90
suspension parts are not allowed to the engine and hood must be identified with
chassis or drive system. the same brand.) 4 2 2x30=60
2. No tie down devices to reduce suspension 4. Full belly pan required. 5 1 1x30=30
travel allowed. Suspension must maintain 5. Added upper tunnel sheeting is not
full OEM travel for the model. 3 The total points issued will be based on a
required. maximum of 50 sleds entered in a class.
3. Commercially available aftermarket shock 6. Additional rear tunnel enclosure not
absorbers that are direct replacement and 4. Points will be awarded for any duly
OEM length for the model are allowed. required. constituted race.
OEM shock location for the model must be
maintained. HILL DRAG 5. Points are non-transferable between
REGIONAL CLASSES regions unless there is a reciprocal
TRACK AND TRACTION agreement between associations to do
Driver divisions otherwise.
1. No track trimming allowed except to clear Stock
heat exchangers. Improved Trail Stock 6. To participate in points and contingency
Pro Mod money the participant must be a current
2. Long track alteration kits that are installed Sno Pro annual member.
by the manufacturer or offered by the King of the Hill
manufacturer as a dealer-installed option General Competition and Safety
will be allowed on any specified model. Stock Classes Rules
The long track alteration kit must be used Stock 500
in its entirety. Stock 600 PADDOCK/STAGING
Stock 700 AND STARTING LINE
FRAME AND BODY Stock 800
Stock 900 1. It is required that full coverage helmets,
1. Commercially available aftermarket Stock 1000 safety glasses and upper body protection
production hoods, side panels, and seats be used in the paddock, staging and
may be used so long as snowmobile Improved Trail Stock starting line areas. All drivers will wear a full
meets filed weight and maintains stock Improved Trail Stock 500 coverage helmet and have tether firmly
appearance. Improved Trail Stock 600 attached whenever they start or move their
Improved Trail Stock 700 snowmobile in these areas.
MOUNTAIN MODIFIED RULES Improved Trail Stock 800
Improved Trail Stock 900 GENERAL REGULATIONS
MODIFIED CLASS WEIGHTS Improved Trail Stock 1000
1. The minimum race weight listed is the Pro Mod
weight of the snowmobile as raced (with Pro Mod 500
fuel). Pro Mod 600
Modified 500 350 pounds minimum Pro Mod 700
Pro Mod 800
Modified 600 350 pounds minimum Pro Mod 900
Pro Mod 1000
Modified 700 400 pounds minimum 1. Full coverage, full face helmets are
Modified 800 400 pounds minimum Sno-Pro mandatory.
Modified 1000 400 pounds minimum Sno Pro Stock 440-600cc
Modified 400 pounds minimum Sno Pro Stock 600 cc and up 2. Sanctioning body personnel (with radios,
OPEN Sno Pro Mod 440-600 phones, and or flags) are the only
Sno Pro Mod 600 cc and up individuals allowed to communicate with a
King of the Hill
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
competitor while on the course. book is required. Snow flap must contact may be removed and holes may be
Communication from sanctioning body the ground with the driver on the sled. The plugged. Premix gasoline may be used.
personnel, race officials or race workers rear snowflap must be retained by ¼ inch
must not provide a driver or his pit crew with reinforced belting meeting the same criteria 10 . Engine must retain OEM for the model
a competitive edge. Pit crews and/or other as the specifications for the Woody’s cooling system concept. Liquid, fan, or free
persons connected with the driver are not provided kit (Woodys Part # “mud-strap”). air cooling must be retained. Cooling
allowed any form of communication with a circuits cannot be modified or removed.
competitor while the competitor is on the IGNITION AND ELECTRICAL Cooling circuit must remain functional.
course. 1. In the event a driver becomes dislodged
3. Drivers may be restricted to the number of 11. Spark plugs do not necessarily have to be
classes they may enter. Four classes per from his sled and the engine continues to OEM.
driver is recommended, but regional run, or the tether switch is not properly
discretion applies. fastened to the driver, the driver will be 12 . The exhaust system as provided by the
4. One driver per machine per class. disqualified from the heat in which the manufacturer for the model. Muffler
5. One driver per entry, per class. infraction incurred. components and /or silencing material must
be intact at all times.
General Snowmobile Rules SNOW HILL DRAG
STOCK 13 . On snowmobiles with OEM electronic fuel
1. The driver’s number must be displayed on injection, commercially available electronic
both sides of the chassis along with class In stock and stock based classes, no control modules may be added to the OEM
designation. These may be permanent or change or modification is allowed unless ECU for the purpose of increasing or
displayed on an approved decal. Individual specifically allowed by these rules. If these decreasing fuel delivery only. The added
numbers must be a minimum of three rules do not specifically allow a change or module must be designed to plug directly
inches high and two inches wide. modification, then it must be assumed that into the OEM ECU and /or the OEM wire
the change or modification is not allowed. harness without modification.
2. All snowmobiles must comply with the
snowmobile general rules and regulations GENERAL SNOWMOBILE REQUIREMENTS DRIVE
section of the ISR rulebook.
1. Snowmobile must begin as a qualified 1. Production primary and secondary clutch
3. Snowmobile may advance to a higher class stock snowmobile. must be used.
and or division without meeting safety
requirements for the higher class as long as 2. The snowmobile must have original OEM 2. Primary clutch and secondary clutch may
the snowmobile advances unchanged and for the model engine, frame, suspension, be modified (no RPM limit).
meets performance rules in the original cowl, fuel tank, airbox, variable speed
class. converters and seat. Named components 3. Any combination of springs. Weights and
DRIVE must be OEM for the model and year, or ramps may be used. These components
properly filed OEM replacement parts that may be interchanged between any
1. The machine must be propelled with a supersede the original OEM parts. Factory brands, providing there is no modification
variable ratio belt transmission. options are not allowed. to the clutch to make the components fit.
TRACK AND TRACTION ENGINE 4. No machining, grinding or welding
1. Drilling or cutting of holes through the track allowed on clutches unless specifically
1. No component of the engine may be stated.
is not allowed except to mount traction altered, changed, reduced or enlarged from
devices. Maximum hole size for mounting the engine manufacturer’s original stock 5. Metal may be removed but not added to
traction devices is 5/16 of an inch. specifications, nor may any additional the primary clutch ramps or flyweights.
components be added to the engine.
2. In all divisions and classes any quantity of Blueprinting of engines is not allowed. No 6. Helixes may be machined for angle
traction screws can be used in the track removal of material whatsoever will be change. No material may be added. No
lugs. Screws must be installed parallel to allowed. This is to include polishing, port welding allowed. Billet helixes will be
the track lug; Screws must not compromise matching, deburring, glass or sand blasting allowed.
the structural integrity of the track. Screws surfaces or material removal for the
must be screwed completely into the track purpose of engine balancing or other 7. Roller secondary clutches not allowed
lug. The shoulder of the screw must contact reasons. unless OEM for the model.
the lug firmly.
FRAME AND BODY 2. Maximum cylinder overbore for wear cannot 8. Drive chain sprockets may be changed
exceed .020 inches (1/2mm). provided that they are options filed by the
1. Sand Paper may be applied to the running manufacturer.
board of the sled. 3. Replacement pistons must be stock OEM
for the model. 9. Drive belts do not need to be OEM.
2. Dulled foot traction devices allowed on the 10. Complete brake system must remain
running boards. 4. There will be no more than one cylinder
a. ON THE FLAT OF THE RUNNING base gasket to a cylinder. No changes in OEM stock for the make and model.
BOARD : engine dimensions can be made by gasket 11. Brake control handle must remain in the
Traction devices must be dulled and be adjustments.
no higher than 1/2 inch above the flat of OEM location (left handlebar, front side).
the base of the traction device. 5. A maximum of one venture per cylinder will 12. Track drive sprockets may be replaced
b. ON TOP OF THE ROLLED EDGE: be allowed in Stock Class. Any exception
Traction devices must be dulled and be must be approved in writing by the ISR with any OEM for the model drive
no higher than 1/4 inch above the top of rules committee. concept (i.e. Involute or external). Unless
the rolled edge of the running board. otherwise specified, no modification
The traction device may extend a 6. OEM carburetor slide valve and allowed to frame, drive, or suspension
maximum of 1/4 inch beyond the side of replacement jet components, without can be made to install replacement
the rolled edge for the purpose of modification, are allowed in all classes. No sprockets.
mounting. There shall be no sharp modification to carburetor body will be
edges to the side of the rolled edge allowed. SKI SUSPENSION & STEERING
3. All snowmobiles in stock and Improved Trail 7. CDI/ECU module may be reprogrammed. 1. Must remain in original mounting location
classes must have a full hood. 8. No Additional fuel pumps allowed. or option location pre drilled or indicated
by the manufacturer.
4. A rear snow flap that conforms to the 9. Oil injection pump must remain in place
General Rules and Regulations section of and remain functional. Lines may be 2. Suspension kits not allowed. No rail
Snow Drag Competition section of the ISR removed and plugged. Oil injector nozzles extensions.
3. Shock absorbers must be OEM for the
model.
4. Limiter strap allowed, but must maintain
an six (6) inch travel.
5. Sway bar may not be relocated. Sway bar
must be OEM for the model, or from a
stock qualified model within the brand.
Sway bar may be disconnected or
removed. If disconnected and not
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
removed, all remaining components must 4. Windshield and windshield molding may be 3. OEM stroke must be maintained.
be secured so as not to endanger driver. removed. 4. The OEM number of cylinders must be
6. OEM handlebar grips may be changed as
long as stock handle bar length is not 5. Protective taping or screening will be maintained.
compromised. The OEM handlebars and restricted to the external openings of the 5. Cylinder head(s) must be OEM for the
handlebar padding must be used. hood only. OEM vent covers and screens,
Handlebar end hooks, (side hill) and which are intended for removal by the model. The cylinder head may be modified
mountain (side hill) straps are allowed. consumer, may be removed. No additional internally including changed replaceable
Brake control handle must remain in the venting allowed. combustion chambers and machining out
OEM location. (Left handlebar-front) of combustion chambers to install inserts.
7. OEM handlebars, padding and throttle 6. The OEM fuel tank is the only tank that can Replacement combustion chambers must
assembly may be interchanged within the be used for fuel supply. Oil tank may not be be commercially available. The visible
brand. (OEM brake assembly for the used as fuel tank. outer portion of the cylinder head or
model must be maintained.) cylinder head cover must remain stock
8. OEM handlebar risers may be used within 7. Tunnel material in all machines in all appearing and the spark plug must
the brand. Commercially available classes must maintain its structural integrity maintain OEM location.
aftermarket handlebar risers, vibration and be free of wear from traction devices. 6. Cylinder must remain within the OEM shell
dampeners and relocation mounts may dimensions to include crevices, bulges,
be used (not to exceed maximum height IGNITION & ELECTRICAL etc. No visible external changes allowed.
of OEM risers). Handle bar risers must be 7. The cylinders may be raised to change
installed using all provided hardware. 1. Ignition must be OEM for the year and port height. If a plate is used to raise
9. No modification to steering post allowed. model. cylinder height, the plate including gaskets
cannot exceed ½ inch, (.500) in thickness.
SKIS & SKI RUNNERS 2. Fixed ignitions may be moved (+ or -) four 8. Engine displacement may be increased by
(4) degrees. cylinder boring to the maximum
1. Any ski allowed. displacement for any Improved Trail Stock
3. Lighting coil must remain in place. class. If so modified, the snowmobile is no
TRACK SUSPENSION 4. Headlight and taillight must be original OEM longer eligible for smaller displacement
classes.
1. OEM for the model suspension must be equipment and must remain in original 9. Engine components allowable for
used. Suspension may be mounted mounting location. Headlight and taillight modification or replacement.
anywhere in the tunnel where the must be operational at the start of the race. a. Bearings
manufacturer has drilled, partially drilled, or Taillight cannot be battery operated. b. Rods-center to center dimension must
marked for mounting holes. Pre drilled 5. Tachometers, speedometers and or heat
plates may be drilled out to facilitate gauges may be installed. OEM gauges remain OEM for the engine.
suspension adjustment. Pre-drilled backing must remain in place. Gauges may be c. Pistons
plate holes may not be enlarged or slotted. disconnected.
6. Aftermarket sensors of any type can only d. Piston pins
2. Track suspension kits are not allowed. e. Rings
3. Shocks must be OEM for the model and be installed in the wye pipe or the exhaust f. Gaskets
canister. g. Reeds and reed blocks may be changed,
remain in OEM location. (external plate may be thicker) if they do
4. .At the discretion of the region, marginal Snow Hill Drag not change outside dimensions for the
Improved Trail Stock cylinder or crankcase. No external
snow wheels along with brackets may be modifications allowed to the crankcase or
added or removed in all classes. Structural In stock and stock based classes, no cylinder to accommodate reed block
supporting components must remain. change or modification is allowed change.
5. Any suspension springs allowed. Spring unless specifically allowed by these 10. Air box may be removed. Air filters may
concept must remain OEM for the model. rules. If these rules do not specifically be used. Internal and external
No chassis or suspension modifications to allow a change or modification, then it modifications to the air box are allowed.
facilitate spring installation allowed. Track must be assumed that the change or 11. On snowmobiles with OEM for the model
suspension must maintain a 6 inch modification is not allowed. Electronic Fuel Injection, the throttle body
minimum travel. including the exterior may be modified for
6. Rear axle idler wheels must remain OEM GENERAL SNOWMOBILE REQUIREMENTS increased fuel flow. No welding of the
for the brand. OEM for the brand rear idler throttle body allowed, this includes no
wheels may be added to the rear axle. No 1. Snowmobile must begin as a qualified welding for repair purposes. Systems that
machining allowed to accommodate axle. stock snowmobile. All snowmobiles must allow increased fuel delivery may be
comply with GENERAL RULES AND used. The stock control module must be
TRACK & TRACTION REGULATIONS SECTION. used. No changes for increased airflow
allowed. Increasing the size of the throttle
1. Unless otherwise specified,the track must 2. Any alterations allowed in stock are body throat not allowed. OEM for the
be OEM for the model. If using a allowed in Improved Trail Stock. model throttle plate (butterfly) must be
replacement track, the track must be used used.
as produced by the molder of the track. No 3. The snowmobile must have original OEM 12. Oil pumps may be removed. Oil injector
other trimming or cutting allowed. Maximum for the model engine, frame, suspension, nozzles may be plugged or removed.
lug height of replacement tracks is 1 3/8 cowl, fuel tank, airbox, and seat. Named 13. No superchargers, turbochargers, or
inch. components must be OEM for the model nitrous systems allowed.
and year, or properly filed OEM 14. Cooling system must be fully operational
2. No chisel studs or grinding on studs replacement parts that supersede the and retain complete stock appearance.
allowed. original OEM parts. 15. Harmonic balancer may not be removed.
16. One additional torque arm allowed (any
FRAME & BODY 5. Improved Trail Stock maximum width style).
dimensions are as produced by the 17. A torque plate is not allowed under
1. Material may be added to chassis and manufacturer. engine or under motor mounting plate.
suspension parts for reinforcement. The 18. Any functionally silenced exhaust
OEM for the model parts must be ENGINE allowed. It is recommended that the db
maintained. No material substitution level (measured at 75 feet down the
allowed. 1. Engine parts must be OEM for the model track, 50 feet from the track, at full
except where noted. The following OEM throttle, with meter to be on exhaust side
2. OEM skid plate may be added for protection engine parts may be modified internally,
of sled bottoms and may not change the but not replaced:
aerodynamics of the sled. Skid plate must
be securely fastened. a. Crankcase
b. Cylinders. (No external fastening devices
3. A rod may be placed in the roll on the edge
of the running board. for mounting cylinders allowed.)
c. Heads
2. The entire external portion of the engine
must be stock appearing.
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
of sled) maximum allowable for winter 3. Drilling or cutting holes in the track is not 1. Engine components must be OEM for the
racing will be 108 db. Contact local allowed, except to mount traction model unless otherwise specified. The
affiliate for local sound regulations. devices. Maximum hole size to mount engine must retain its complete external
19 . Exhaust must exit stock location. traction devices is 5/16 inch. stock appearance and dimensions.
DRIVE 4. For traction devices other than traction 2. Cylinders must be OEM for the model.
screws, maximum width of traction Must remain within OEM shell dimensions
1. Any primary and secondary clutch may devises is two (2) inches. The traction to include crevices, bulges, etc. No visible
be used. devises must be secured with at least external changes allowed. Number of
two hardened steel fasteners. Hardened cylinders must be OEM for the model. No
2. Jackshafts of like material may be steel fasteners must not protrude more external fastening devices allowed to
changed to accommodate a clutch than ½ inch from the flat of the traction secure or hold cylinders in place.
change. No welding allowed to device.
accomplish this change. 3. Engine displacement may be increased by
5. No chisel studs or grinding on studs cylinder boring to the maximum
3. Track drive axle and chaincase must allowed. displacement for any Sno-Pro class. If so
remain OEM for the model and remain in done, the snowmobile is no longer eligible
OEM location. FRAME & BODY for smaller displacement classes.
4. Any OEM for the brand track drive 1. Any chassis alterations, additions or 4. Crankshaft and crankcase must be OEM
sprocket allowed. Unless otherwise removals, which alter stock appearance for the model. OEM stroke must be
specified, no modification allowed to or dimensions are not allowed. maintained.
frame, drive, or suspension to install
sprockets. 2. Tunnel can be repaired but must maintain 5. Cylinder head(s) must be OEM for the
OEM length. model. Billet heads may be used as long
5. Complete brake system must be OEM for as outside appearance is not changed.
the make and model. 3. The OEM fuel tank must be the only tank
that can be used for fuel supply. Oil 6. Engine components allowable for
6. On snowmobiles that comply in all injection tanks may not be used as a fuel modification or replacement.
respects with the Improved Trail Stock tank. a. Bearings
class rules, the modified class safety b. Rods (rod center to center must
shield around the brake mechanism is 4. Insulation foam may be removed from remain the same)
not required when advancing to the engine compartment. c. Pistons and rings
modified division. d. Piston Pins
5. Tunnel material in all machines in all e. Gaskets
SKI SUSPENSION & STEERING classes must maintain its structural f. Reeds and reed blocks may be
integrity and be free of wear from traction changed, (external plate may be
1. Brake control handle must remain in the devices. thicker) if they do not change the
OEM location (left side, front side of bar). outside dimensions of the cylinder or
IGNITION & ELECTRICAL crankcase. No external modifications
2. Any commercially available handlebar allowed to crankcase or cylinder to
allowed. Mountain bars not allowed 1. Ignition must be OEM for the model. accommodate reed block change.
CDI/ECU may be replaced with a unit from
3. No modification to steering post allowed. any stock qualified model within the brand. 7. Airbox may be removed. Air filters may be
4. Any spring may be used on the Flywheel and stator may be modified. used. Internal and external modifications
may be made to the airbox.
suspension. 2. Fixed ignitions may be moved (+ or -) four
5. Must maintain 6’’ (inches) of vertical (4) degrees. 8. Carburetors, flanges and intake manifold
must be OEM for the model, and OEM
suspension measured at the front bumper. 3. Lighting coil must remain in place. appearing, internal modifications are
4. Electrical wiring must remain in place. allowed.
SKIS & SKI RUNNERS 5. Headlight and taillight must be OEM
9. Oil pumps may be removed. Oil injector
1. Any commercially available aftermarket or original equipment. Glass lenses must be nozzles may be plugged or removed.
OEM for the brand ski (including multi taped over with transparent clear tape.
keeled and multi cutting edge skis) may be Lights must remain in original mounting 10. One additional fuel pump is allowed. No
used. OEM skis must be from a stock location. Headlight and taillight must be other type of additional fuel delivery
qualified model. operational at the start of the race. Taillight system allowed.
cannot be battery operate
TRACK SUSPENSION 11. No superchargers, turbochargers or
SNO-PRO nitrous systems allowed.
1. Track suspension may be located
anywhere in the tunnel where the In stock and stock based classes, no 12. Harmonic balancer may not be removed.
manufacturer has drilled, partially drilled, change or modification is allowed unless Any commercially available harmonic
or marked for mounting holes. Pre Drilled specifically allowed by these rules. If these balancer may be added. Engine must
plates may be drilled out to facilitate rules do not specifically allow a change or retain external stock appearance.
suspension adjustment. Pre Drilled modification, then it must be assumed that
backing plate holes may not be enlarged the change or modification is not allowed. 13. Any functionally silenced exhaust allowed.
or slotted. Must exit downward, rearward and extend
GENERAL no more than 3 inches from chassis.
2. Slide rail extensions allowed.
3. Any suspension springs allowed. Spring 1. Snowmobile must begin as an ISR stock DRIVE
qualified model. All snowmobiles must
concept must remain OEM for the model. comply with GENERAL RULES AND 1. Any primary and secondary clutch may be
No modification to frame or suspension REGULATIONS section. used.
allowed when installing springs.
2. Any alterations allowed in Stock are 2. Jackshaft may be changed to
TRACK & TRACTION allowed in Sno-Pro. The sled must have accommodate a clutch change. Must be
1. Any commercially available one-piece original OEM for the model or factory like material. Titanium jackshaft not
designated replacement engine, frame, allowed unless OEM for the model. No
molded rubber track allowed. Track must suspension, fuel tank and seat. welding allowed on jackshaft.
be race designated by the molder of the
track. No cleated tracks allowed. Unless 3. Sno –Pro maximum width dimensions are 3. Track drive axle and chaincase must be
specified, no modification to drive, frame as produced by the manufacturer. OEM for the model.
or suspension allowed to install track.
Maximum lug height is 1 ½ inch. ENGINE 4. Jackshaft, track drive axle and chaincase
2. Unless otherwise specified, the track must be in OEM for the model position.
must be used as produced by the molder
of the track. No trimming or cutting 5. Complete brake system must remain OEM
allowed. for the model.
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
SNOW DRAG RACING
6. Track drive sprockets may be replaced. within the brand. Flywheel and stator may 1. Any commercially available one-piece
Drive or chassis modifications to install be modified. molded rubber track allowed. Track must
sprockets not allowed unless specified. 2. Lighting coils must remain in place. be race designated by the molder of the
3. Wiring and instrument cables may be track. No cleated tracks allowed. Unless
SKI SUSPENSION & STEERING removed. specified, no modification to drive, frame or
4. Headlight and taillight must be original suspension allowed to install track.
1. Brake control handle must remain in the OEM equipment. Must remain in original
OEM location (left, front side of mounting location. Must be operational at 2. Drilling or cutting holes in the track is not
handlebar). the start of the race. Taillight cannot be allowed, except to mount traction devices.
battery operated. Maximum hole size to mount traction
2. Any commercially available handlebar 5. It is allowed to add tachometers, devices is 5/16 inch.
allowed. Mountain bars allowed. speedometers, or heat gauges. OEM
gauges must remain in place and may be 3. Any or all track lugs may be trimmed, to a
3. Any suspension springs allowed. Spring disconnected. minimum height of 1 inch. The structural
concept must remain OEM for the model. integrity of the track must not be
Pro Mod Class compromised.
4. No modification to steering post allowed.
GENERAL 4. For traction devices other than traction
SKIS & SKI RUNNERS screws, maximum width of traction devises
1. All snowmobiles competing in the Pro Mod is two (2) inches. The traction devices must
1. Any commercially available aftermarket or class must comply with GENERAL RULES be secured with at least two hardened steel
OEM for the brand ski (including multi AND REGULATIONS SECTION. fasteners. Hardened steel fasteners must
keeled and multi cutting edge skis) may be not protrude more than than ½ inch from the
used. 2. Race Director shall have the authority to flat of the traction device.
determine structural integrity. TRACK SUSPENSION
2. Minimum ski length is forty (40)) inches.
TRACK SUSPENSION 3. Snowmobile must be stock appearing and 1. Must maintain 6’’(inches) of vertical
have a unique identification number. suspension measured at the rear bumper.
1. Track must be OEM or OEM designated Chassis serial number must be permanently
replacement for the brand and model. affixed to the side of the tunnel in the area FRAME AND BODY
of the right side footrest.
2. Track suspension may be located 1. Tunnel material in all machines in all
anywhere in the tunnel where the 4. The combined weight in all classes is to be classes must maintain its structural integrity
manufacturer has drilled, partially drilled, 625 pounds minimum. and be free of wear from traction devices.
or marked for mounting holes. Pre-drilled
plates may be drilled out to facilitate ENGINE 2. The hood must have top and side cowling
suspension adjustment. Pre-drilled 1. Any engine allowed. Engine must not and must contain at least one thousand
backing plate holes may not be enlarged three hundred (1300) square inches of
or slotted. exceed displacement limit for the class. surface. As a requirement to receive
2. Maximum overbore is defined as 2% over contingencies the hood must be identifiable
3. Slide rail extension plates are allowed. as an OEM style hood. Engine and hood
Structural integrity must be maintained. the cc displacement limit of the class. brand designation must match in order to be
The Race/Tech Director shall have the 3. Any functionally silenced exhaust system considered for contingency programs.
authority to determine structural integrity.
allowed. The exhaust emission pipe must KING OF THE HILL
4. Any suspension springs allowed. Spring not protrude more than three (3) inches
concept must remain OEM for the model. beyond the chassis or hood configuration. NATURALLY ASPIRATED
1. 1000 CC MAXIMUM
5. Rear axle idler must remain OEM for the SKI SUSPENSION AND STEERING 2. No lowering (OEM suspension or
brand. OEM rear idler wheels may be
added to the rear axle. Rear axle maybe 1. Brake control handle must remain in the comparable travel.
changed to accommodate the idler OEM location (left side, front side of bar).
wheels and rear axle fitment. No NON ASPIRATED
machining allowed to accommodate 2. Sled overall width is open. 1. 1300 cc maximum
axle. 3. Any commercially available handlebar 2. One (1) power added allowed.
TRACK & TRACTION allowed. WEIGHT
4. Must maintain 6’’ (inches) of vertical 1. Minimum combined weight shall be 550
1. Any commercially available one-piece
molded rubber track is allowed. suspension measured at the front bumper. pounds, snowmobile and driver.
Modifications to chassis or drive to install SKIS & SKI RUNNERS
track not allowed unless specified. DRAG RACING COURSE
1. Any commercially available aftermarket or
2. Drilling or cutting of holes through the OEM for the brand ski (including multi COURSE DESCRIPTION
track is not allowed except to mount keeled and multi cutting edge skis) may be
traction devices. Maximum hole size 5/16 used. 1. Sanctioned Drag Racing events shall be
inch. held on a flat course of grass or dirt,
FRAME & BODY 2. Minimum ski length is forty (40)) inches. completely free of obstructions which
DRIVE provides adequate and safe run-off area at
1. Any chassis alterations, additions or the end of the racing course so that
removals, which alter stock appearance or 1. Carbon fiber brake discs are allowed. competitors may exit and safely slow down
dimensions are not allowed. Fuel tank and 2. Aluminum brake discs not allowed. upon completion of the race. (See
seat must be OEM for the model except as 3. The clutch cover must be separate of the suggested course layout diagram in
noted in Stock class rules. Appendix.)
cowl configuration and cover the clutch
2. Tunnel can be repaired but must maintain perimeter and faces to the center of the 2. Blend the end of the course (run-off area) to
OEM length. clutch bolt or below. Must be .090 inch 6061 existing terrain conditions. No banks,
T6 aluminum or equivalent steel material fences or walls.
3. The OEM fuel tank must be the only tank the outer perimeter must be covered with 6
that can be used for fuel supply. inch belting. No other clutch cover material 3. Promoter shall provide adequate crowd
are allowed. If .125 aluminum or steel is control to prevent spectators or any other
4. Lubricating tanks may not be used as a used, belting is recommended but not
fuel tank. required. Snowmobiles with removable side
panels may fasten clutch covers/ shields to
5. Removal of any insulation, which alters the side panels to meet this requirement.
outside stock appearance, is not allowed.
TRACK & TRACTION
IGNITION & ELECTRICAL
1. Ignition must be OEM for the model. CDI
unit may be from any stock qualified model
12-13 ISR SNOWMOBILE RACING YEARBOOK PAGE
SNOW DRAG RACING
persons from moving onto the racing course a. Entrants in all classes will race two at a
or run-off areas. time. Winners advance until two
4. The finish line will be isolated from all competitors remain to race in the final
unauthorized personnel by a fence one heat.
hundred (100) feet in circumference away
from the track edge. b. Promoter may, at his discretion, race
5. A 1/2 inch four (4) x four (4) sheet of double elimination heats which require
plywood will be required, behind each lane, every driver to lose two (2) races before
at the starting line. the driver is eliminated from
competition.
COURSE LENGTH
c. Match eliminations may be raced at
1. Other than maximum course length and Masters or Amateur Drag racing events.
minimum lane width, variations in course
dimensions may be approved by each 3. BRACKET RACING
region, but will not be accepted in a. Upon entry, each competitor must
determining ISR timing records. specify the precise elapsed time he/she
will not exceed during the course of
2. Maximum course length for snow drag racing.
racing is 660 feet. b. Entrants in all classes will race against
the clock for elapsed time. A minimum
COURSE WIDTH of two (2) and a maximum of four (4)
snowmobiles may race at one time, at
1. Minimum lane width is twenty five (25) the discretion of the Promoter.
feet. c. Heat winners will be determined by the
driver who comes closest to his/her
DRAG RACING FORMATS predicted elapsed time without
exceeding the predicted elapsed time.
The following rules apply to all ISR Exceeding the predicted time means
sanctioned Drag Racing events. There disqualification.
may be some variations in this format from d. Heat races continue until the final heat,
region to region. All such variations must when the winner of the class will be
be advertised for the information and decided by the system noted above.
convenience of the competitors. e. Points will be awarded to the four final
drivers, in order of closest to elapsed
ORDER OF CLASSES times.
1. Order of classes to be run will be NO EXPRESS OR IMPLIED WARRANTY OF
determined by the Promoter and properly SAFETY SHALL RESULT FROM
publicized or posted for the convenience PUBLICATION OF OR COMPLIANCE WITH
and information of competitors. THESE RULES AND REGULATIONS. THEY
ARE INTENDED AS A GUIDE FOR THE
ELIMINATION HEATS CONDUCT OF THE SPORT AND ARE IN NO
WAY A GUARANTEE AGAINST INJURY OR
1. In all classes, up to six (6) snowmobiles DEATH TO SPECTATORS OR
will race per elimination heat. Heat PARTICIPANTS.
qualifiers will advance until up to six (6)
finalists remain. Up to five (5) finalists will
earn points towards the end of the season
points championships in each class.
2. Points will be awarded only to the driver of
the snowmobile.
3. Elimination heat formats may be raced at
Masters or Amateur Drag racing events.
SPECIAL EVENTS
1. TIMED ELIMINATIONS
a. Entrants in all classes will race for
elapsed time on the course. Fast times
will be basis for qualification in finals.
b. No snowmobile may exceed the pre-
established elapsed time for its
assigned class.
c. Any snowmobile that exceeds the pre-
established elapsed time will
automatically be advanced into the next
higher class for duration of the racing
season.
d. Winners will be determined by head to
head competition, but within the
maximum elapsed time limits
established. (Note: elapsed times will
vary according to the type of racing
surface).
2. MATCH ELIMINATIONS
PAGE 12-13 ISR SNOWMOBILE RACING YEARBOOK
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