Lisbon Classes

Classes for 74 and older models (Lisbon Rules)

Fan Cooled Twin to 300cc (Lisbon Rules)

  1. 1975 and older models may compete
  2. 300cc and under twin cylinder engine displacement may compete.
  3. No studs
  4. Carbides allowed
  5. No jackshaft models
  6. General rules for 74 and older classes apply

Fan Cooled Twin to 340cc (Lisbon Rules)

  1. 1975 and older models may compete
  2. 340cc and under twin cylinder engine displacement may compete.
  3. No studs
  4. Carbides allowed
  5. No jackshaft models
  6. General rules for 74 and older classes apply

Fan Cooled Twin to 440cc (Lisbon Rules)

  1. 1975 and older models may compete
  2. 440cc and under twin cylinder engine displacement may compete.
  3. No studs
  4. Carbides allowed
  5. No jackshaft models
  6. General rules for 74 and older classes apply

Sport 300 Enticer / Citation (Lisbon Rules)

  1. Up to 1983 Yamaha Enticer / Ski Doo Citation / Moto Ski Mirage ONLY
  2. 300CC and under Single or Twin cylinder engines may compete
  3. No ski spreaders.
  4. No studs
  5. Carbides allowed
  6. This class is 100% stock with NO modifications or alterations of any type.
  7. May also enter Sport 300 Plus

Sport 300 plus Enticer / Citation (Lisbon Rules)

  1. Up to 1983 Yamaha Enticer / Ski Doo Citation / Ski Doo Mirage ONLY
  2. Yamaha 340cc twin and under / Ski Doo – Moto Ski 377cc and under may compete.
  3. No ski spreaders
  4. No studs
  5. Carbides allowed
  6. This class is 100% stock with NO modifications or alterations of any type.

HD Super Stock (Lisbon Rules)

  1. 1973 and older chassis
  2. 1973 and older single cylinder engine only. Brand must match chassis.
  3. Over bore allowed
  4. Any type stock muffler, no expansion chambers or tuned exhaust allowed.
  5. No Reed or Rotary valves allowed
  6. Point Ignition only, no CDI allowed
  7. Float type carbs allowed
  8. HR port sleds may enter this class

HR stock single cylinder (Lisbon Rules)

  1. Must be a production line model offered to the public in 1973 and older with a fan cooled engine.
  2. Example : Arctic Cat / Puma, Cheetah, Panther, Lynx with and 1973 or older Arctic Cat fan cooled engine. Ski Doo / NTN, Olympic, Elan with any HR port fan cooled engine 1973 and older.
  3. Fan cooled engine only with HR port
  4. Engine must be available for model year.
  5. Example: Arctic Cat may run / Kohler, Sachs, JLO, Kawasaki or Hirth of any CC
  6. Over boar allowed to .060
  7. No Porting / stock ports
  8. Stock carb or float type replacement will be allowed. NO flat slides, carb bore must be smaller than the port.
  9. Stock muffler only.
  10. Point ignition only, no CDI
  11. No Reed or Rotary valves
  12. Stock suspension only
  13. Carbides allowed, 4 inch maximum carbide length.
  14. Shocks are permitted on skis.
  15. Stock clutch or 94c Duster / Bowerblock drive clutches are permitted.
  16. ¾ inch lug track / stock length for model permitted.
  17. Ski Spreaders allowed.

Free Air Stock 250/340/440 (Lisbon Rules)

  1. Must be a production model as a 1978 or earlier model. No limited production race sleds such as Z , SR or Blizzard.
  2. Stock Reed and Rotary valve engines allowed.
  3. Stock Clutches, Drive and Driven
  4. Stock Exhaust only , OEM twin pipes allowed, no “aftermarket” tuned exhaust allowed
  5. 34mm carb bore max. 440cc may use up to 38mm. No flatslides.
  6. No studs
  7. Stock Steel skis only
  8. This sled in 250cc / 340cc size is also allowed in the 50 Plus class. No 440cc F/A in 50 Plus.

50 Plus (Lisbon Rules)

  1. Fan cooled twin cylinder engine 440cc and under may compete.
  2. 1975 and older sleds / engines may compete. Must be OEM for model and year.
  3. Drive clutch may be OEM or Comet 94c duster / powerblock.
  4. Driven clutch OEM
  5. Brakes may be upgraded but must remain original mounting and mounting location.
  6. Carbides allowed
  7. No internal or external engine modification allowed.
  8. No programmable ignitions.
  9. Exhaust must be OEM for model without modification.
  10. General rules for 1974 and older apply.

IFS Class (Lisbon Rules)

This class is limited to the sleds and years listed below only!
Arctic Cat Cougar 1985 to 1990 & AFS Jag 1989 to 1991   /   Ski Doo 1988 1989, Stratos
Safari 1990 to 1993 368,440,503cc   /   Yamaha 1985 to 1995 Phazer
Polaris 1985 to 1992 Indy Trail 488 & 440 cc Indy Sport 340 & 440 cc
  • Fan cooled engine with functioning fan. Must have original style ignition.
  • No performance kits, OEM/aftermarket ex. GYT kits. Heads, cylinders, exhaust, ignition, carburetors.
  • Chain case must be original, must maintain stock clutch covers, must have primary clutch covered.
  • Skis: Stock replacement type skis of any manufacturer. No aluminum/plastic skis/skins. Up to 6 inch carbide only, no additional keels or runners. Runner will not stick down more than 9/16” from bottom of ski. No ski spreaders.
  • Brakes will remain stock for year, make, and model
  • Tracks: Original/stock replacement to 3⁄4” lug height. No longer than 121”. Changing track drivers is allowed. No cleated tracks. No special racing or “R” tracks, no cut down width tracks. No traction devices of any design or size.
  • Clutch: You may change gear ratio, clutch springs/weights. Secondary clutches must be stock for year, make, model can change helix and spring.
  • Suspension: Stock rear suspensions for year, make, and model no changes from stock. Stock front suspension, no widening or any other changes from stock.
  • Handlebars: Must be original bars for the year, make, and model. They may be reinforced but cannot be extended or raised. Hooks ARE permitted. No bending or straightening of bars is allowed.
  • Fuel tanks: Must be factory fuel tank for year, make, and model only and secured safely.
  • Motor regulations: *Fan cooled motors only. Fan must remain operational. *Motor must be an available option for the chassis entered in the race.
  • Reeds must be OEM, no aftermarket. Original primary clutch for year, make, and model only, no aftermarket replacement types. Carburetors are original size and type for year/make/model of sled/ motor being run. Jetting can be changed and airbox can be removed, oil pumps can be removed. Original exhaust for year/make/model. Pistons are stock replacement up to .040” oversize allowed. No port grinding, only edge chamfering. Must have stock port sizing. Bead blasting for cleanup only, cannot remove casting lines/port material. No porting /polishing of any type on any internal parts.