2009
600cc Micro Sprint Universal Engine Rules
- Terms and conditions
• Internal Stock parts – must use original manufacturer parts for the particular
year and make engine except where noted. No mixing of parts from different year
and make engines, even if made by the same manufacturer. Non stock external
bolt on parts may be used (example: billet oil pan, starter, water pump cover, oil
cooler, pipes, etc.)
- Overall Engine
• Must be a Production Motorcycle Engine, 4 cylinder, 4 stroke
• Current year engines allowed
• No Titanium anywhere in or on the engine, unless it comes stock form
manufacturer of engine on the production bike
• Must have engine, clutch, and transmission all in one unit
• Must be Chain Drive
- Bore and stroke
• 600cc Maximum for engine model that was new in 2006 and up. Other
engines are 637cc maximum. Engine model is defined as a manufacturer redesign
of overall engine. See Specification list. In the racing year starting in 2013
displacement may not exceed 600cc on any engine.
• Standard Stroke only (no strokers)
- Head and cams
• NO PORTING, Blending the Bowls, or Blending the Valve Seats (exhaust or
intake) Valve jobs are acceptable.
• Cams do not need to be stock, but the lift must be no greater than stock.
(duration is open)
• Cam timing may be adjustable
• May use any valves, but they may be no larger than stock valves.
• Head may be resurfaced
• Any head gasket may be used
- Pistons
• Any Piston may be used, must be within cc limit specified under bore and
stroke
- Bottom End
• No machining to remove weight from the crank (no after-market cranks) (no
lightweight cranks)
• Stock connecting rods must be used (no after-market rods)
• Aftermarket rod bolts may be used
- Clutch/Transmission
• The clutch does not need to remain stock, but must remain operable
• Transmission gears must be stock, no close-ratio gears or nonstandard gearratios
• All gears must remain in transmission, no removing any gears.
- Ignition
• Stock Rev Limiter must remain intact at all times (ex: no switched or gear
specific limiters). No hot ECU boxes, no modified ECU boxes. Factory race
boxes are ok, but must have the rev limit set to the street bike stock rev limit. If a
computer is hooked up to check the ECU it must be set to factory stock
specifications, no tolerance. See specifications list for RPM limits.
• All cars must have the PA standard connector for the track to check engine
rpm rev limit. These are available from the chassis manufactures and engine
builders, and at the track. All cars must leave intact the rpm wire coming from the
ECU.
• Stock appearing ignition must be used (no after-market ignition systems,
factory race ignitions are ok) may use different year ignitions from same
manufacturer as long as stock rev limit of engine (not ignition) is retained.
• No aftermarket coils
• Engines that came with stock fuel injection may use an after-market add ons
(example: Power Commander, Dim Sport) to adjust the fuel curve and/or timing
(essentially the same as adjusting jetting and using an ignition advancer).
• Ignition advancers may be used
- Induction system
• No mechanically forced induction (turbo charging, supercharging)
• Any carburetors may be used on any engine, regardless of year of engine.
• If the engine did not come from the factory with fuel injection, fuel injection
may not be used.
• If the engine came with factory fuel injection, the fuel injection may be used
and may be converted for use with alcohol. The stock fuel injection throttle bodies
must remain, but may be modified for use with alcohol. Any number of injectors
may be used regardless of stock number of injectors.
- Exhaust
• Any exhaust may be used, as long as there is a muffler included with the
system that will keep noise levels within individual track limits.
- Charging system
• The stock original factory charging system may not be removed, and must
remain in complete working order. No factory racing charging systems.
- Self Starting
• The engine must self-start at the beginning of the event. If it does not selfstart,
the car may be pushed off and must start at the rear of the event as the
penalty.
- Fuel
• Alcohol or gasoline may be used, no exotic fuel additives, non flammable top
lube only, no fuel enhancer top lube.
• Fuel tanks must contain a bladder. A fuel tank with a bladder is further defined
as a plastic outer shell with a rubber inner container.
- Minimum weight
• Minimum weight at all times is 775 pounds, car and driver. If weight is added
it must be firmly bolted in place.
