ISDRS PISTON PORT OUTLAW RULES
Piston Port Outlaws This class was created to allow an affordable class in Racing where sleds and equipment are cheap and readily available. All rules efforts will be made in an attempt to keep costs down and ALL COMNPETITORS ON A LEVEL PLAYING FIELD. *Effective Immediately all sleds in PPO must use factory made independent front suspension chasis. Mono-leaf sleds will not be allowed in PPO and will have to run in either mod or vintage classes depending on how the sled meets the rules criterias in those classes. (Ex. It is illegal to put a Indy 600 triple Polaris motor on a TX chasis) Classes offered will be 600 cc Maximum and 700 cc Maximum. A 3% overbore will be allowed in all classes. (Example max CC�s will be 618 in the 600 class and 721 cc�s in the 700 class) Minimum 2 sleds entered to make a class. Additional classes may be added in the future if there is enough support to form a new class. *All motors must be piston port only motors. (Absolutely no reed, reed assist, case reed, rotary valve or etc. will be allowed) *Snowmobile must externally look like the stock sled and year you are claiming it to be. Serial numbers do not have to match. Exterior lightweight parts (i.e. suspension components) may be used but may not change sleds external appearance except for the skis. External lightweight parts must be as strong as OEM replacements. Lightweight jackshafts, drive shafts and brake rotors are not allowed. This rule is both for safety reasons and to keep costs down for the class. *All Carburetors must be Mikuni Round slide carbs. 38 mm carb bodies max. Carbs may be bored. (Most of the sleds during the piston port era came with Mikuni 38 MM Round slide carbs) *Motors may be interchanged within same brand. (example, it would be illegal to put a Polaris motor in a Yamaha chasis.) *All motors must use stock crank, case and cylinders, water cover and stock ignition system. (absolutely no stutter boxes or MSD ignitions) Inserts on the heads may be used but may not alter the external appearance. Engine Rules are the same as they would be in the Imp. Stock classes. *Any commercially available track with a minimum lug height of .5 inches. Other than studding, track should be run as produced. Any safe and functional rear suspension allowed that has 2 inches of compression travel is allowed. *Fuel will be any commercially available fuel that is non oxygenated. No performance enhancing fuels will be allowed. Weight: Drivers in full gear should weight approximately 180 lbs. If driver is under 180 lbs. extra ballast must be added. Fuel can be added at 1gallon = 7 pounds of weight or additional ballast can be securely fastened to top of running boards. Safety: All sleds must have functional tether cords. 2 Inches Minimum Compression Travel Front and rear. Any commercially available ski, front of ski loop must be at least 6 inches high. All sleds must have functional silencers on exhaust system. Stud penetration will be a maximum of � past the top of the lug height. All other general safety rules apply, see general rules.
