Microsprints Rules

Micro-Sprint Class Specifications: StarLite Speedway has three micro-sprint classes that compete. The three classes are: 125cc, 270 Open and 600 Combined.

1A) 125cc 2-Stroke (250cc 4-Stroke) Class Specifications:
1.) Driver Age: Driver shall be at least 12 years old or older.
**Revised 3/7/09** Exceptions: 10 years old with at least 2-years of racing experience.
2.) Minimum Weight: Car and Driver: 580 lbs w/125cc 2-stroke engines.
3.) Engines:
a.) Motors must be single cylinder
2-stroke engine not to exceed 132cc
4-stroke engine not to exceed 250cc
b.) Only dirt bike or ATV motors allowed (no shifter kart motors, boat motors, or road race motors). A motor                      consists of lower cases, cylinder, head and components.
c.) Motor modifications are allowed. Modifications must meet StarLite Sprinters race club engine and tech                          specifications.
d.) Engines must remain chain-driven off of original transmission counter shaft.
e.) Aftermarket cool-heads with adjustable domes are legal.
f.) No Stroker Motors Allowed.
4.) Fuel:
a.) All 125cc class motors must use readily available pump gasoline only!
5.) Chassis: See general tech and safety rules.
a.) Maximum rim diameter is 10 inches.

1B) 270 (450cc 4-Stroke Open Class Specifications

1.) Drivers Age: Driver shall be at least 14 years old or older,
13 years old with at least 1-year micro-sprint or equivalent experience.
12 years old with at least 2-years micro-sprint or equivalent experience.


2.) Minimum weight: car and river 610 lbs.
3.) Engine Rules:
a.) All motors must be single cylinder
2-stroke based engine not to exceed 270cc.
4-stroke based engine not to exceed 450cc.
b.) No engine age restrictions.
c.) Engines must remain chain-driven off original transmission counter shaft.
d.) Modifications are allowed, must meet speedway engine tech specifications.
4.) Fuel: Any approved fuel (alcohol, gasoline) and approved oils (see fuel specifications in rulebook.
5.) Chassis: See general, technical, and safety rules.

1C) 600 Class Specifications

1.) Driver Age: Driver shall be at least 14 years old or older.


2.) Weight: 600cc class minimum 775 lbs, wingless weight 750 lbs, after the feature race.
3.) Terms and Conditions
a.) Internal Stock parts  must use stock original manufacturer parts for the particular year and make engine,                      these parts cannot be modified except where noted, if the rules do not state that you can do it, you cannot do                it. No mixing of parts from different year and make engines, even if made by the same manufacturer. Non                      stock or modified stock external bolt on parts may be used (example: billet oil pan, starter, water pump cover,              oil cooler, pipes, valve covers, etc.)
4.) Overall Engine
a.) Must be a Production Motorcycle Engine, 4 cylinders, 4 stroke. No limited production race motors allowed,                   only US street legal bike motors are allowed.
b.) Current year engines allowed.
c.) No Titanium anywhere in or on the engine, unless it comes stock form manufacturer of engine on the                             production bike.
d.) Must have engine, clutch, and transmission all in one unit.

e.) Must be Chain Drive.
f.) Manual cam chain tensioners are allowed.
5.) Bore and Stroke
a.) 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.
b.) Standard Stroke only (NO Strokers)
6.) Pistons
a.) Any piston, piston rings, and wrist pin, may be used, must be within cc limit specified under bore and stroke.
b.) After market coatings are allowed on pistons only.
7.) Bottom End
a.) No machining to remove weight from the crank ( no after-market cranks) (no lightweight cranks.

b.) The stock unmodified connecting rods must be used (no after-market rods)
c.) Aftermarket rod bolts may be used.
d.) Modifications to oil pump system, oil pick up and oil passages are allowed.
e.) No dry sump systems are allowed unless it comes from the motorcycle manufacturer as original equipment.
8.)Head and Cams
a.) NO PORTING or Blending the bowls.
a.) The clutch does not need to remain stock, but must remain operable.
b.) Transmission gears must be stock, no close-ratio gears or nonstandard gear-ratios.
c.) All gears must remain in transmission, no removing any gears, No lightweight or modified stock gears.
a.) Stock Rev Limiter must remain intact at all times (ex: no switched or gear specific limiters. No hot ECU boxes,             no physically 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.
b.) 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.
c.) 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.
d.) No aftermarket coils.
e.) Engines that came with stock fuel injection may use an after-market add on components. (ex: Power                               Commander, Dim Sport) to adjust the fuel curve and /or timing (essentially the same as adjusting jetting and               using an ignition advancer).
f.) Ignition advancers may be used.
g.) No gear position sensor may be used. The sensor may be in place on the engine, but cannot have any wires                    connected to it. Gear position wire from ECU may not be switchable.
h.) No traction control device.
i.) Only one ECU box present in or on car.

11.)Induction System

a.)No mechanically forced induction (turbo charging, supercharging).

b.) Any carburetors may be used on any engine, regardless of year of engine.
c.) If the engine did not come from the factory with fuel injection, fuel injection may not be used.
d.) 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.
a.) 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. (less than 98 decimals)
13.)Charging System
a.) The stock original factory charging system may not be removed, and must remain in complete working order.              No factory racing charging systems.
b.) Flywheels can be modified.
14.) Self Starting
a.) The engine must self-start at the beginning of the event. If it does not self-start, the car may be pushed off                     and must start at the rear of the event as the penalty.
15.) Fuel
a.) Only alcohol, gasoline, and/or top lube may be used. Non flammable top lube only, no exotic fuel additives,                   no oxidizers, no fuel enhancer top lube.
16.) Minimum Weight
a.) Minimum weight at all times is 800 pounds, car and driver. If weight is added it must be firmly bolted in                       place.

2.) General Micro Sprint Technical Specifications: All Micro-Sprint classes must follow general specifications unless class has specific rule(s).

2A) General

1.) Inspections: All cars will be subject to safety and technical inspection prior and after competing. Cars must meet speedway safety and technical specifications in this rulebook unless noted otherwise.
2.) Technical inspection of cars may be omitted at weekly races.
3.) Minimum Car Weight Measurement: All car weights are measured with the car and driver as they come off the track immediately following an event.
4.) Brake Lines: Cars must use steel brake line, Kevlar stainless braided Teflon brake hose or DOT approved rubber brake line for brake plumbing. No exposed plastic tubing allowed.
5.) On Board cockpit adjusters are allowed.

2B) Engine

1.) Maximum Engine Displacement:
a.) Conversion of Units: Cubic Centimeters (cc) to Cubic Inches (cu in):
16.287cc = 1.000 cu in.
Millimeter (mm) to inches: 25.4 mm = 1.000 in.
Displacement: 125cc = 7.628 cu in, 270cc = 16.476 cu in, 600cc = 36.614 cu in.
b.) The maximum overbore allowance for engine type is:
125cc Class
125cc single cylinder overbore allowed not to exceed 132cc
Most newer motors this is 1mm (.040)
250cc 4-Stroke must be stock bore & storke

270cc Open Class
2-Stroke single cylinder any bore, any stroke, not to exceed 270cc
4-Stroke single cylinder any bore, any stroke, not to exceed 450cc

Covered on pages 11, 12, and 13

c.) Measurement Method #1: using oil volume: (P&G method)
-Mandatory on engines susceptible to this type measurement as the first check on the displacement of an                       engine. If there is doubt, a tear down must be made. Remove the spark plug, turn the engine to top dead                         center, and fill the engine with oil through the spark plug hole to overflowing. Fill measured container with                   the correct amount of oil for the engine when set to bottom dead center.
d.) Measurement Method #2: using calipers and hand tools
– In order to find the displacement of a cylinder:
– 1.) Measure to bore (cm)
– 2.) Divide the bore by 2 to get the radius
– 3.) Square the answer to (2) and multiply by 3.14(pi)
– 4.) Multiply the answer from (3) by the engine stroke (in cm).
– The final product is the cylinder displacement
– For single cylinder engines, this number (4) must be less than or equal to the max engine                                                  displacement value.
– For multiple cylinder engines, multiply (4) by the number of cylinders.
This value must be less than or equal to the max engine displacement.

2C) Chassis/Drive Train

1.) Wheelbase: Minimum 50 inches / Maximum 70 inches. Measured center of front axle to center of rear axle.
2.) Tread Width: Minimum 32 inch / Maximum outside the tire width 62 inches measured with template that slides         over the outside of the wheels.
3.) Any wheel size and tire combination that is available may be used, but it may not exceed 22 ½ inch in height.                 **22 ½ inch hoop must pass over a tire anytime it is checked.**
4.) Wheels and rims must be attached to the car axles using a minimum of 3 lug nuts or bolts to hubs, or use knock-         off wheel centers with splines and/or single nuts.
5.) Any car equipped with a shifting mechanism must have this device mounted in the compartment. Shift levers may       be mounted outside of driver’s compartment on opposite side of car from the chain driver.
6.) Only a foot operated throttle permitted. At the discretion of the tech-inspectors, a safe, well-engineered hand               throttle may be used if the driver cannot operate a foot throttle because of loss of limb or paralyses.
7.) Fabrication of critical parts of the car must be electric welded. No brazing or solder critical parts are identified as         follows:
Frames Running Gear attached Brackets
Cowl Frames Back Rest
Bumpers Nerf Bars
Front Axle
8.) Cars must be equipped with a roll cage. The roll cage must be sufficient strength to support the weight of the car         and driver being certain that the roll cage will keep the fuel tank form touching the ground and avoiding rupture         in case of upset. At the top of the roll cage cross-members must be secured by more than one welded support               (Gussets). Roll cage must be a minimum of three inches above driver’s helmet.
9.) Roll cage shall be at least:

1 inch 0.062 wall thickness
1-1/8 inch 0.065 wall thickness
1-1/4 inch 0.065 wall thickness
Roll cage shall be made of 4130 condition N (chromoly steel) or material equivalent in
strength with a 1/8-inch inspection hole drilled in it for the measurement of material used. The front section of           the roll cage must be no further back than the steering wheel. Roll cage must have sufficient fore and aft                         bracing. Bends must have at least three-inch radius. No square or pointed corners permitted.
10.) Nerf Bars: All cars must be equipped with side nerf bars. Side nerf bars must extend to inside edge of the tire but         not beyond the outside of the tire.
11.) Front/Rear Bumpers: Cars must have bumpers extending beyond the front and rear tires. Nothing may extend            beyond a tangent line from the outside edge of the tires to the bumpers. Nothing may extend beyond the outside          edge of tires or wheels, whichever is the widest point. No sharp corners or design so as to hook or damage other          competitor’s vehicles.
12.) Steering: Front wheels must be connected by solid or tubular tie rods.
13.) Any material used for purpose of adding weight must be bolted or clamped safely (no zip-ties) as a part of the              cars structure. No liquid or loose ballast i.e. water, fuel, oil, sand bags, rocks, log chains, etc allowed. Weights                must be painted white with the cars number painted on it in black. Minimum 2-5/16 bolt up to 10 lbs 2-3/8 bolt         over 10 lbs of weight. Loss of weight on track will result in the black flag for that event as a safety violation.
14.) Mirrors: No rear view mirrors or any item positioned in such a way that it can be used as a rear viewing device.
15.) Fire Wall: There must be a metal firewall between driver and engine compartment. The minimum thickness                 specifications are steel: 24 gauge (0.024) or aluminum: 0.063
16.) Floor Pan: Car must have complete under-pan extending from the front of the seat to a place forward of the                   drivers feet. This floor pan must be made out of aluminum (min. 0.040) or Sheet Steel (min. 0.024) and                         fastened securely to the chassis with bolts, rivets, or quarter-turn (Dzus) fasteners.
17.) Radios: All drivers have to purchase a one way radio for the 2017 racing season.

2D) Body/Wings

1.) All cars must have complete sprint car design bodies only. Front engine cars may remove 125 sq. in. (excluding            nose opening) for cooling. All rear engine mounted cars using solid material for tail may remove up to 250 sq. in.        of tail section for cooling. Perforated tail sections may be used so long as they’re formed in an attractive manner          and shape. Exhaust stacks are the only part of the engine to extend through tail section regardless of the body              style. Covers not required on side-mounted motors. Carburetors, air cleaners, and exhaust stacks are accessories        and need not to be covered.
2.) Tail sections must be in place for the initial green flag of time and all races. If after the initial green flag has flown       and the tail comes loose, the car shall be sent to the infield. In the infield the loose section may be removed. The           car may come back onto the track safely.
3.) All cars must be painted an attractive color or colors. Body or shell of the car must be made of aluminum, metal,         fiberglass or high impact plastic.
4.) Top Wing: Wings will be allowed. Sideboard, right side max. 54 by 24. Sideboard left side max. 54 by 24. 25% of         sideboard must carry car number and be a minimum of 12 inches tall. Sideboards air foil section and sides must           cover center foil. All wings must have a 1/16 radius. No raw edges. No wood or wood products to be used in wing         construction except rib and spar within center section (air foil).
5.) Nose Wing: If a nose wing is used, it may not exceed 18 x 30 and installed so as not to obstruct the drivers                     vision. The nose wing must carry the car number originally used on the body nose.
6.) Mudguards are legal only if constructed of aluminum or fiberglass. There will be no plastic mudguards, side                 panels, tops or body encasements allowed. Maximum height of mud guard or sissy bar to be no less then 15                   from the center of roll cage out on a vertical drop. Up to 12 sq. ft. in all wing classes.

2E) Car Numbers

1.) All cars must have legible numbers on the car surfaces described below that are in clearly contrasting colors to the      background color (i.e. white background with black numbers). Numbers must be present on the car at the nose,          both sides of the tail and sideboards of the wing (if used). Car number to be separated from advertising so that            they will stand out and be readable to the scorers. The Head scorer after practice day or your first race of the                season will decide on legibility of numbers. If number style turned down, they must be changed by the next race          event.
Minimum sizes: nose: 8 tall Tail Piece: 10 tall Wing: 12 tall.
2.) The first place driver in season points in all classes will have the privilege of using his/per final position (number          1) as his/her number the following year.

3.) Micro Sprint Safety Regulations: All Micro Sprint classes must be following general specifications unless class has       specific rule(s).

3A) General Regulations

1.) Safety inspections may be conducted at all races.
2.) Any car or diver may be disqualified by the safety or pit steward for any infraction of safety specifications.
3.) All nuts, bolts and component parts of each cars suspension system chassis and running gear must be secured            with either lock nuts, lock washers, star washers, cotter keys or safety wire except wheel nuts when using quick            change hubs.

3B) Driver Equipment: (MUST be worn by driver when on track)

1.) Helmets must be of an approved competition type. Helmets must be full head coverage type and must meet Snell        2010 or better helmet safety standards.
2.) Only unbreakable goggles or approved shields may be used and must be worn in proper position anytime a car is         in motion on the track.
3.) All drivers will wear a name brand flame-retarding uniform.
4.) Seat-belts, shoulder harnesses and arm restraints are mandatory. Safety belts must be securely attached to the             car and used at all times. Arm restraints shall be adequate to keep the drivers hands below the top of the roll cage.
5.) All drivers will wear full-hand coverage gloves. (leather and or flame retarding).

3C) Engine and Related Systems

1.) Overflow Protection: For radiators and oil tanks: Car must have overflow tubing running to below the bottom               frame rail or to a sealed catch tank.
2.) Fuel Tanks: All fuel tanks must be fastened to the chassis securely with bolts and/or steel banding. No rubber               cords or nylon tie-downs. All tanks must have a check valve and/or long vent line running below bottom level of         tank to keep fuel in tank in the event of a roll over.
3.) On and off switches must be on dash, top of the cowl, or on steering wheel. Switch must be connected and                     functional. On and off position must be clearly marked.
4.) All wet cell batteries mounted in the cockpit must be covered and vented outside the cockpit area.

3D) Chassis / Suspension

1.) Chain guards will be installed on all cars where chains are exposed to the driver and/or other participants. The             chain guard, using a minimum or 0.090 aluminum material or equivalent will run on top of the chain from front         of front sprocket to the vertical center line of the rear sprocket. The guard must be installed in such a manner that       the driver cannot touch the chain and/or sprockets when sitting in the cockpit.
2.) No car will be allowed to compete that requires dismantling portions thereof to enter or leave the cockpit, with             the exception of steering wheel hubs steering wheel attached with approved hub no bolts or nuts, head nets are           exempt from this rule.

3.) Brakes will be of sufficient strength so as to slide the wheels or sufficiently stop the car while in motion on the               track.
4.) There shall be no accessories such as rear hubs, brake disc or driver sprockets welded to the rear axle.

4D) Fuel Specification and Procedures: **Used for all classes of racing at StarLite Speedway**

1.) All fuels are to be approved: See specific class rules for fuel types allowed. See approved fuels below.
2.) All mixing oils are to be club approved: Only approved mixing oil may be added to the fuel. See approved list.
3.) Fuel sampling, hydrometer testing will serve as a means of determining if a sample or samples should be                       submitted to an approved laboratory for testing, as well as making them available for individual protests. Fuel             samples should be taken and inspected by the technical steward/inspector, referee or an elected club officer.                 During the taking of the fuel sample, and inspection should be made of the fuel system. Any unusual containers,         lines or means of transferring fuel (other than the main line from the tank to the carburetor or injector pump)              will be subject to thorough inspection and grounds for disqualification and suspension.
4.) Fuel sampling, hydrometer testing and inspection may be done at any weekly race by the referee and tech                     inspectors decision.
5.) The cost of general fuel testing shall be paid by driver/owner with the results being mailed to the secretary. The            Executive Board will choose the lab.
6.) The owner, driver and the vehicle will be suspended for thirty days and loss of accumulated points from the date         of infraction, if a competitor of car is found in violation of this rule. Reinstatement will require the payment of the       fine of $100 and the cost of the lab test. The driver must pay lab fee before being allowed to continue racing (see         suspensions/disqualification rules).

**Note** power enhancing or octane boosting oil mixes will not be allowed
(i.e. Klotz goldlabel, etc.)