340 Mod / Air Cooled Open Combo
This combo class allows air cooled sleds 550 cc and under, with stock exhaust systems to race against 340 mod class sleds. Liquids that qualify for the 340 mod class may compete. 340 Mod class liquid guidelines apply for liquid sleds competing in this class.
340 mod rules 
  1. 340 cc max
  2. Air cooled engines may have any aftermarket exhaust system
  3. Liquid cooled engines must run their stock unmodified single pipe exhaust system.
  4. Leaf sprung chassis 1985 and older may compete.
  5. Any drive or driven clutch
  6. No EFI / must be naturally aspirated engines.
  7. Any carb allowed
  8. Engine brand must match chassis brand.
  9. Any track, ¾ lug max
  10. Studding allowed, 3/8 max above track lug.
  11. Carbides allowed.
  12. Any internal or external engine modifications allowed on air cooled engines.
  13. No internal or external modifications on liquid engines.
  14. Any chaincase, any gears, any sprocket size
  15. Skis may be any commercially available steel, plastic or aluminum ski of leaf spring design. Springs must be steel and functional.
  16. Brakes may be upgraded and the location may be moved, shielding must be in place if disc is moved to the driveshaft.
 
Air Cooled Open Rules
  1. F/C or F/A engine 550cc and under may compete.
  2. 1985 and older sleds / engines may compete, must be leaf sprung.
  3. Drive clutch may be OEM or Comet 102 / 94c duster / powerblock
  4. Driven clutch OEM
  5. Brakes may be upgraded but must remain original mounting and mounting location.
  6. Carbides allowed
  7. studding allowed
  8. Handlebars may be modified or replaced with any commercially available handlebar. Hooks may be added.
  9. No programmable ignitions
  10. Exhaust must be OEM for model without modification.
  11. Internal Engine modifications allowed.
  12. Any carb allowed, no EFI
  13. Skis may be any commercially available steel, plastic or aluminum ski of leaf spring design. Springs must be steel and functional.