Pro-Stock
ENGINE
1. No component of the engine may be altered, changed reduced or
enlarged from the engine manufacturer’s original stock specifications,
nor may any additional components be added to the engine.
Blueprinting of engines is not allowed. No removal of material
whatsoever will be allowed. This to include polishing, port matching,
deburring, glass or sand blasting surfaces or material removal for the
purpose of engine balancing or other reasons.
2. Stock Airbox must be as factory provided and no altering is
allowed
3. Maximum cylinder overbore for wear cannot exceed .020 inches.
4. Replacement pistons must be stock OEM for the model.
5. There will be no more than 1 cylinder base gasket to a cylinder. No
changes in engine dimensions can be made by gasket adjustments.
6. A maximum of one venture per cylinder will be allowed in stock
classes.
7. OEM carburetor slide valves and replacement jet components, without
modification, will be allowed in all classes. No modification to carb
body will be allowed.
8. On snowmobiles equipped with electronic fuel injection, it is legal to
replace the non-adjustable fuel pressure regulator with any
commercially available, mechanically adjustable fuel pressure
regulator. (no electronically controlled pressure regulators 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 machine.
9. No additional fuel pumps may be added to stock carbs.
10. Oil injection pump must remain in place and functional. Lines may be
removed and plugged. Oil injector nozzles may be removed and holes
plugged. Premix gasoline may be used.
11. Except for quick disconnects and flow directional valves engine must
retain original cooling concept. Liquid, fan, or free air cooling must be
retained. The cooling circuits cannot be modified or removed.
Thermostats may be removed. When the sled is on the course the
cooling fluid must flow unobstructed thru out the entire cooling system.
(no short circuiting) Trail stock machines are not allowed to alter
cooling the system
12. OEM heat exchangers for the model located under the tunnel may be
relocated any place on the top, side, or under the tunnel and remain
functional.
13. Harmonic balancer may not be removed.
14. The complete OEM exhaust system must be used and furnished and
filed by the manufacturer
15. Electronic computer module (ECM) may be added to adjust the
fuel mixture on EFI Sleds.
16. Commercially available pistons (i.e. Wiseco) may be used if OEM
are not available. May not increase stock bore size beyond 0.020
inches.
DRIVE
1. Any springs, ramps or weights may be used. There is no maximum
clutch engagement RPM.
2. NO machining on clutches to accommodate spring and weights.
3. In the primary clutch, metal may be removed but not added to ramps or
flyweights.
4. Secondary clutch cams may be cut to any angle. Billet helixes allowed.
5. No overdrive machining.
6. Drive belts do not necessarily have to be OEM equipment to in stock
classes.
7. Any drive chain and sprockets may be used. Same material as OEM
8. Any track sprocket and driver allowed. Driver or sprocket must be
of like material as factory. Extroverts not allowed unless OEM.
SKI SUSPENSION & STEERING
1. Any steel or titanium suspension springs allowed. OEM for the model
design concept must be retained.
2. Limiter strap allowed to limit travel, but must maintain two (2) inches
of travel with driver on the sled. (No sled lowering allowed in trail
stock. Sled must be within 1 inch of stock ride height.)
3. Ski widening devices and/or height adjustment devices are not allowed
in stock class unless furnished as OEM and filed properly.
4. Shocks must remain OEM for the brand and remain in the OEM
location. On rebuildable shocks, spacers may be added internally to
limit rebound travel, but not compression travel.
5. Handle bar extensions will be legal. All ends must be plugged.
6. Handle bars with mountain handles may be replaces with handlebars
from within the brand.
7. Radius rods may be located anywhere on the trailing arm where the
manufacturer has drilled or partially drilled for radius rod mounting
holes.
SKIS & SKI RUNNERS
1. Aftermarket skis allowed. Skis must be commercially available and
marketed through normal sales activity. Minimum aftermarket ski
length must be 40 inches. Ski width may not be trimmed. Skis may not
be interchanged between brands. Replacement ski must be the same
material as OEM ski for the model.
2. Skis may be reinforced but must remain in original configuration. This
reinforcing must be on the upper surface of the ski only.
3. Ski loop must be designed to prohibit ski interlock with any other
components while driver is on the machine.
TRACK SUSPENSION
1. The complete suspension must be used as furnished and filed by the
manufacturer. There will be no suspension options permitted in stock
classes. Track suspension may be located anywhere in the tunnel
where the manufacturer has drilled or partially drilled for mounting
holes. Pre drilled plates may be drilled to facilitate suspension
adjustment. Pre drilled backing plate holes may not be enlarged or
slotted.
2. Any steel or titanium suspension spring allowed. Torsion springs (not
coil springs) may be shortened at the long end to prevent contact with
the track. OEM for the model design concept must be maintained.
3. Limiter straps allowed to limit travel, but must maintain two (2) inches
of travel with driver on sled. (lowering not allowed in trail class) Idler
wheels must remain OEM stock.
4. Marginal snow wheels and related hardware may be added or removed.
Structural integrity must be maintained. Rear axle idler wheels must
remain OEM for the model. OEM for the model rear idler wheels may
be added to the rear axle.
5. Shocks must remain OEM for the model and remain in OEM location.
On rebuildable shocks, spacers may be added internally to limit
rebound travel, but not compression travel.
6. No device may be added that stops the suspension from going thru its
normal bottoming action.
7. SLIDE LUBERS ALLOWED.
TRACK & TRACTION
1. The track must be OEM for the model year or a commercially
available 0.5 inch lug speed track of 13.5 to 15 inches in width.
Original OEM track must be used in TRAIL STOCK.
2. No cutting, trimming or shaving of the track, grouser bars, rubber
studs/snow lugs will not be allowed. May be narrowed down water cut preffered. The track must be used as
produced by the molder of the track. Acceptable traction products
allowed.
3. Minimum lug height from the flat of the track is .500 inch.
4. Track may not be reversed.
5. On rubber tracks, track clips and guide clips may be replaced when
worn. Guild clips may be removed and replaced with track clips. Track
clips may be removed and replaced with guide clips. The track must
retain the number of clips with which it was produced.
6. Stud length may not exceed 0.75 inches over the lug height.
FRAME & BODY
1. Any chassis alterations, additions or removals which alter stock
appearances or dimensions are not allowed.
2. Tunnel can be repaired but must remain OEM for the model length.
3. Windshield and windshield molding may be removed.
4. No additional venting allowed.
5. Protective taping or screening will be restricted to external openings
only.
6. A minimum of 2. 5 inches of clearance under the Bulkhead.
7. No seat modifications are allowed in the stock classes.
8. Headlight assembly must be intact and functional.
IGNITION & ELECTRICAL
1. Ignition must be OEM for the model and year.
2. CDI module may be reprogrammed.
3. Fixed ignitions may be moved (+/-) 4 degrees.
4. Lighting coil must remain in place.
5. Stock class must have all gauges installed but may be unhooked.
(Trail stock requires all gauges to be functional.)
6. Electrical wiring must remain in place.
7. Headlights may not be removed. Must remain functional.
8. Data Loggers are allowed in the Stock Classes
