International Snowmobile Racing (ISR) Rules and Classes are used as published under these sections, unless otherwise specified below
- General Rules and Regulations
- Oval Sprint Competition
- Vintage Oval Competition
ISR rules Year Book can be purchased from Wahl Bros Racing: http://www.wahlracing.com
If these rules do not specifically allow a change or modification, then it must be assumed that the change or modification is not allowed
All classes where rule is referring to “Frame or Chassis” this means tunnel and bulkhead
IFS – X class
exception to IRS rule #1 (only 82 or older IFS single track limited production OEM racing snowmobiles allowed no non OEM, aftermarket or custom design allowed)
- 1985 and older Polaris Indy chassis allowed in ORA IFS-X classes
1992 or older standard production Polaris Indy model. Engine & mount, jackshaft, chain case, and exhaust must remain in original locations.
- 1. ENGINE - 340 cc FUJI (Polaris L/C) engine only. May bore .040 over stock bore. Any clutches, no roller secondary.
- 2. IGNITION, EXHAUST, CHAIN CASE, AND CARBURETOR - Stock OEM and size for model, air box may be removed.
- 3. CHASSIS - Engine & Mount, Jackshaft, Chain case, exhaust, must remain in original locations. No Indy Lite chassis.
- 4. FRONT SUSPENSION - 42" Maximum width between carbides. Maximum 1" offset (each ski to the right, 1") Springs, shocks, sway bar & Link, radius rods, trailing arms may be changed or modified but must fasten to stock locations. 2.5" minimum travel at front of bulkhead. Reinforcing allowed.
- 5. REAR SUSPENSION - Stock rear suspension components only, Except shocks, springs and limiters. Components may be moved, removed, or relocated.
- 6. CHAIN CASE, DRIVESHAFT, JACKSHAFT - OEM for model.
- 7. TRACK - 15" x 121" OEM or OEM replacement, no racing (R) rubber track.
- 8. BRAKE, DRIVERS, HOOD, STEERING, SKIS, SEAT & FUEL TANK - Any.
SUPER STOCK 400 Single Cylinder
1985 or older
- ISR Super Stock Rules apply
SUPER MOD 400 Single Cylinder
1985 or older
- ISR Super Mod Rules apply
LATE MODEL 440
CHAMP, SPRINT, DAVCO, SNOPRO, PRODUCTION SLEDS. 45" max width. Max CC - 440 L/C or F/A, 503 f/c. Must comply with ISR general safety rules
PRO STOCK 440
2007 or older production single pipe IFS sleds. (Indy, XCR, Pro X, ZR, ZL, SnoPro, MXZ, MXZX, etc.) No rider forward chassis: (03 and up Skidoo Rev, 02 and newer Arctic Cat SnoPro, 05 and newer Polaris IQ.)
- 1. ENGINE - Stock for model and year, 440 cc max. No modifications.
- 2. CHASSIS - No modifications except, windshield may be altered or removed. Headlight may be removed and reinforcing allowed. Engine, jackshaft, chain case and exhaust must remain in original location.
- 3. IGNITION; PIPE; CHAINCASE; JACKSHAFT; DRIVESHAFT; HOOD; BELLYPAN; SEAT and FUEL TANK - Stock for model.
- 4. SILENCER - OEM or commercially available for model. No modifications.
- 5. CARBURETORS - Stock OEM for model, original size.
- 6. SKIS – Handlebars and Clutching Any.
- 7. TRACK - Any rubber track in good condition, Stock length and width for model.
- 8. REAR SUSPENSION - Any OEM Production Suspension. Stock OEM components only, except springs, shocks, limiters. Components may be moved, removed, relocated, or modified.
- 9. FRONT SUSPENSION - Stock OEM components for model except springs, shocks sway bar and link may be changed but must fasten to stock locations in bulkhead. Trailing and A-arms may be modified to accept shocks and sway bar link. Stock width- no offset
500cc Fan IFS
1992 or older standard production Fan cooled IFS Sleds
- 1. ENGINE - 92 and older engine of the size and type that was available in chassis model. no external modifications except engine stop/torque-arm, Internal modifications allowed. May bore .060" over stock bore. Oil injection may be disabled. Newer engines unchanged in design/performance allowed. 1992 and older Rotax 503's may be placed into a 1992 and older IFS Skidoo stock qualified chassis.
- 2. CHASSIS - Stock OEM no modifications, reinforcing allowed. engine mounts and exhaust must remain in original location. May be widened to meet the 40" width rule (Only stock f ront end components may be used to widen front end) . Sway bars may be added or reinforced.
- 3. IGNITION - Stock OEM or OEM replacement for engine, non-programmable.
- 4. EXHAUST - Stock OEM for model.
- 5. CARBURATOR - Any production carburetor except flat slides. Air box may be removed. no fuel injection. Stock size.
- 6. CLUTCHES - Any OEM , no roller secondary. No aftermarket adjustable weights.
- 7. CHAIN CASE - OEM for brand. This is to allow hydraulic brakes..
- 8. REAR SUSPENSION - OEM for model. Wheels may be swapped with other "Stock qualified" wheels no Wahl Racing ect. Snowmobile must retain a minimum of 2" of travel. No remote adjusters.
- 9. TRACK - Any rubber track in good condition. No "R" racing tracks.
- 10.HOOD - Correct for the model. Windshield may be altered or removed.
- 11. BRAKES - Any.
- 12. FUEL TANK -Any but MUST remain in stock location.
- 13. SKI'S. - Any.
- 14. SEAT- OEM for brand seat may be cut down but must retain stock shape and minimum of 3" of height.
- 15. DRIVESHAFT, JACKSHAFT, DRIVERS, STEERING - OEM for model.
- 16. FRONT SUSPENTION - OEM for model front end components (minus sway bar adding or swapping.) 40" Carbide center to center width. Snowmobile must retain a minimum of 2" of travel.
- 17. No exotic metals
1998 or older Note: This is a stock based class. No limited or Special Purpose built machines. This class is intended to be a entry level inexpensive stock based class
- 1. ENGINE - Must match chassis brand. No external modification. May bore .040 over stock bore.
- 2. EXHAUST - Any pipe.
- 3. CHASSIS - Windshield and headlight may be altered or removed and reinforcing allowed. Dash and unnecessary brackets may be removed. Stock OEM hood and belly pan. No Indy light chassis allowed.
- 4. IGNITION - Stock OEM for engine.
- 5. CARBURETOR - Stock OEM for engine, original size, air box may be removed.
- 6. CLUTHES - Any OEM primary, Stock OEM for brand secondary. Must be 1998 and older.
- 7. CHAIN CASE - OEM for model.
- 8. FRONT SUSPENSION - Stock OEM for model. Springs, shocks, sway bar link, radius rods, and tie rods may be changed but must fasten to stock locations on bulkhead/tunnel. Trailing arms-OEM for model, this may be modified to accept shocks, sway bar links and rear perch. 2.5 min. travel front suspension.
- 9. REAR SUSPENSION – Any OEM rear skid and components. Springs; Shocks and limiters may be moved, removed, relocated. No Aftermarket rear skids.
- 10. TRACK – Any rubber track in good condition
Rules updated as taken from ORA website on 12/27/11. Rules given Revision level and posted to website
Updated per 2012 ORA Spring Rules Meeting:
- Super Stock: “Hot Stocker” rule removed
- Pro Stock 400 Single name changed to Super Stock & ISR Super Stock rules adopted
- Super Mod 400 Single class added
- ’92 & older 500cc Fan IFS class added
- Sportsman600 now allow any OEM Skid and R – rated tracks
- IFS-X exception to ISR rule #1 added to allow 1985 and older Polaris Indy Chassis