Drive
Must retain OEM clutches. Springs,weights,ramps,helix may be changed.
Gear ratios and chain may be changed.
No machining of clutch surfaces.
Track and Suspension
Speed tracks are allowed in stock classes. Minimum 0.500 inch lug height.
OEM suspension must be used,addition or removal of wheels permitted.
Enviromentally friendly lube systems allowed.
OEM ski's or aftermarket ski's must be a minimum of 40 inches.
Must retain OEM drive sprockets.
Suspension must retain 2 inches of front and rear travel
Rear idler wheels must retain stock diameter.
Frame and Body
Operational kill switch and tether cord is manditory.
All factory installed componants must be present and un modified. Hood, Ski's, Frame, Gas tank, Carbs, Air box, Suspension, Seat.
No drilling or lightening of sled permitted.
Engine
No componant of the engine may altered, changed, reduced or enlarged from the
engine manufacter original stock specifications. Nor may any additional componants be added to the engine.Blue printing of engines is not allowed. No removal of material whatsoever will be allowed. This is to include polishing, port matching, deburring, glass or sand blasting surfaces or materinal removal for the purpose of
engine balancing or other reasons.
No more than one cylinder base gasket to a cylinder.
No aftermarket reeds, reed spacers, pipes,cans, air boxes, carbs.
Oil injection must be functional if equiped from factory.
No turbo or Nitrous allowed.
Drive
Any brand of clutches permitted. Springs,weights,ramps,helix may be changed.
Gear ratios and chain may be changed.
Machining of clutch surfaces permitted.
No light weight drive shafts or jack shafts.
Track and Suspension
Speed tracks are allowed in stock classes and Improved, minimum of 0.500 lug. No cleated tracks allowed.
OEM front suspension must be used,addition or removal of wheels permitted.
Idler wheel size and material change permitted.
Enviromentally friendly lube systems allowed.
OEM ski's or aftermarket ski's must be a minimum of 40 inches.
Frame rails must remain OEM, replacing or modifying rear suspension arms allowed.
Suspension must retain 2 inches of front and rear travel.
Frame and Body
Operational kill switch and tether cord is manditory.
Hood, Seat, Gas tank, Front suspension, must be OEM.
Engine
Improved stock 500-900.
Must retain OEM cylinders, porting and polishing,balancing,blueprinting allowed.
must maintain stock carbs but may be modified.
Engine may be bored to a class cc limit. A 1% overbore limit allowed.
OEM carbs must be used but may be modified.
Air box modification or removal allowed.
Oil pump may be removed or disabled.
Cool down systems allowed.
Heat exchangers may be modified or removed.
Aftermarket reeds,reed spacers, pipes, cans allowed.
No turbo or Nitrous allowed.
Improved stock 1000
Same as Improved stock 500-900 but with these exceptions:
Improved stock 1000 allowed aftermarket carbs.
Engine may be bored 1% overbore.
Oem stroke may be changed.
Any aftermarket cylinder allowed.
Pro Stock 1000
Drive
Same as Improved stock 1000 with the exception of light weight drive/jack shafts.
Track and Suspension
Carpet tracks allowed. No cleated tracks allowed.
Aftermarket front and rear suspension allowed.
Any shocks allowed.
Suspension must retain 2 inches of front and rear travel.
Aftermarket mini ski's allowed.
Frame and Body
Operational kill switch and tether cord is manditory.
Removal of wiring and guages and componants allowed.
Chassis and bulkhead must remain OEM. Lightweight hoods and body parts allowed.
Seat must be OEM appearing and appear stock.
Fuel cell allowed.
Engine
Same as Improved stock 1000 but with these exceptions:
Crankcase must be OEM for make of sled.
Cylinder overbore limited to 2%.
No 4 cylinder engines unless a Yamaha Vmax based prostock motor.
No turbo or Nitrous allowed.
Prostock up to 1250cc
Same as Prostock 1000 with these exceptions:
Seats do not need to remain OEM appearing.
4 cylinder engines allowed.
Engine max displacement of 1250cc with a maximum overbore of 2%.
Same as Prostock 1000 with these exceptions:
Clutch covers must be reinforced and enclose both clutches.
Seats do not need to remain OEM appearing.
Engine bottom ends may be watercraft based or snowmobile based.
Engines may have any amount of cylinders.
Turbo and Nitrous are allowed.
Max engine displacement of 1500cc.
No cleated tracks.
Must retain 1 inch of suspension travel ft. and rear.
Mod Lay Down 1250-1500
Lay down chassis with maximum engine displacement of 1500cc.
Engine bottom ends may be watercraft or snowmobile based.
Nitrous and turbo allowed.
Front and rear suspension must have 1 inch travel.
Manditory kill switch and Tether cord operation.
Must be driven by a variable ratio belt drive transmission.
Clutch covers must be reinforced and cover both clutches.
No cleated tracks.
Chain cases must be enclosed.
Open Mod Full Body 1500+
Same as Mod Full Body but with no engine displacment limit.
Open Mod Lay Down 1500+
Same as Mod Lay Down but with no engine displacment limit.