1973 and Older HR Stock Single Cylinder
1973 and older HR port sleds may compete.
  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.
  14. Shocks are permitted on skis.
  15. Stock secondary only.
  16. Stock clutch or 94c Duster / Power block drive clutches are permitted.
  17. ¾ inch lug track / stock length for model permitted.
  18. Seat must be stock appearing
  19. No adjustable handlebars
  20. Skis must be steel
  21. Studs allowed, 3/8 max above lug.
  22. Ski spreaders allowed, 3 inch max.