2009 Restrictor Class Rules

1)	AGE
	Drivers age 9 and up may compete in the Restrictor Class. A copy of birth certificate or state issued photo ID must be provided for any driver under the age of 18.

2)	CAR IDENTIFICATION
	All Restrictor Class cars must have a clearly visible "R" on the nose or nose wing of the car. All car running a fuel injected engine must also have a "I" in the same location.

3)	SHOCKS
	Any shock absorber legal, except no cockpit adjustable.

3)	TIRES and WHEELS
	Any wheel size and tire combination may be used, but tires may not exceed 22 1/2 inches in height. Wheels must be held on with 4 or more standard lug nuts or knock-off hubs. Right rear tire must be plated NMMA, ASCS2 or MD-57, a minimum 50 durometer compound Hoosier or American Racer tire. Tire may be be siped or grooved. Tire durometer check should be done at least 15 minutes after the races to allow for cool down.

5)	WINGS
	Cars must run a 10 square foot maximum top wing with a one piece center section (no multi stage airfoil wings allowed). Airfoil must be parallel with roll cage and no offset sideboards (front to rear). No Twisted wings. Sideboard right side, maximum 18” tall x 48” long. Sideboard, left side, maximum 24” tall x 48” long. Sideboards may not extend more than 3 inches beyond the center section. No mechanical, electrical or hydraulic adjustments are allowed in the cockpit area. Wing must not extend beyond tires as driven. Nose wings optional. If a nose wing is used, the center section may not exceed 18” x 24” with sideboards no larger than 9” tall x 21” long.

6)	STAGING AREA
	Once a car enters the staging area it is considered race ready. No legality changes may be made. If a car is not legal once it reaches the staging area it will be disqualified for that specific event.

7)	COCKPIT ADJUSTMENTS
	Functioning cockpit adjustments are NOT allowed.

8)	SELF STARTING
	All cars must be self starting. Any car requiring a push vehicle from the staging area will start at the tail of that race.

9)	ENGINE RULES
	4 cycle multi-cylinder engines not exceeding 600cc with stock bore & stroke with charging unit.
	Valve jobs will be allowed as long as they are within mfg. tolerance allowance. Any air cleaner will be allowed. Any exhaust will be allowed. Crank case ventilation to atmospheric pressure only is allowed.

	Carburetors must be OEM Production Motorcycle, CV style. No Flatslides or Lectron style
	carburetors allowed. Carburetors may have metering rods, jets and springs changed to tune fuel curve to match the car requirements. TPS sensors not required. Any motor sprocket (520 or 530) is allowed. Outer cosmetic changes will be allowed to mount the motor in the car (i.e. cut part of the engine off to get it to fit, relocate oil pan drain plug, etc.).

	Fuel Injected Engines running Carburetors
	Engines originally equipped with Fuel Injection are allowed with any OEM production Motorcycle CV Style Carburetors and aftermarket filter boxes. Must run same make as motor. Interchanging of Injected and Carbureted cylinder heads is allowed. Engines must be run with the OEM/Stock Ignition system from either the carbureted or injected engine, using the unaltered, stock, Motorcycle OEM components. No MSD, MoTec, Tec3, or any other aftermarket ignition systems allowed. CDI black box must be stock and unaltered.

	All engines must start out as 600cc factory fuel injected engines. They must run the OEM throttle bodies and the correct number of injectors for the engine. They may run methanol or track approved gasoline. They may run a Power Commander for fuel map only. At this time due to the tracks inability to produce restrictor plates each person will be responsible for producing their own plates.

	The restrictor plates must be run between the throttle bodies and the engine. They must be a flat plate constructed of a non corrosive material not less than .030 thick and not more than .090 thick. They must fit tight in the manifold boots and have a maximum of one .750 Max. round hole, no tolerance will be allowed. All plates must be inspected, approved and marked by the officials of Miami County Speedway.

	There should be nothing between the throttle plate and the intake valves that is designed to enhance the airflow through the restrictor opening. This includes anything, either added to or machined into the carburetor, manifold or boot, head, etc that would create a cone shape to the airflow entering or exiting the restrictor. Anything that appears to be specifically designed to enhance airflow through the restrictor will be judged illegal.

	Billet boots are OK. But they should be the same shape used for the non-wing class. The walls should have a relatively consistent cross section area and be shaped similar to stock units.

	Any car that chooses to run a fuel injected engine in the Restrictor Class must weigh 775 lbs
	minimum and have an "I" in the same location as the "R".

Engine Tech Items
	Restrictor size - .750 Go, .7505 No Go - in I.D. - as stamped, round hole in center
	Installed in the top half of boot, fitting in the groove snuggly
	Kawasaki & Yamaha OD - 1.658 min.
	Honda OD - 1.600min.
	No alterations
	Stock bore & stroke - 600cc
	Cam Shafts - stock, OEM, unaltered in proper location
	Cam Gears - stock, OEM, unaltered bolt holes, unaltered bolts
	Intake & Exhaust Port Areas - "as cast", no grinding, polishing or porting
	Ignition trigger wheel/advancer - stock, OEM, unaltered in any way, CDI box matching trigger
	wheel A.K.A. signal rotor.
	Flywheel - original stock, OEM charging system must be intact, unaltered and in place

Engine Tech Items (continued)
	CDI / ECU "Black Box" - stock OEM - unaltered.
	All transmissions gears intact and functional
	No cones in carburetors or air box
	Clutch must be FUNCTIONAL