2012 Micro Sprint Rules


1” Diameter Min., .090 wall min. steel tube (Sprint style cage)

Minimum 4 uprights on cage per side.

Driver must exit outside of car.

Frame width 26” maximum.

Frame length 85” maximum.

Front and rear axies must not exceed frame, 78” wheel base maximum.


Age 12 years minimum. Snell / Dot in good condition

Up to 650cc parallel twin or single cylinder (up to 650cc’s displ.Maximum)

Maximum 2-stroke 270cc.

No fuel injected models allowed. Engine must come from the factory with carbs. Aftermarket carbs are allowed.

Must be stock bore and stroke (clean-up boring up to 1mm boring allowed; no big bore kits)

Right rear wheel must be 3-piece aluminum or heavy gauge steel.

Must have foam in fuel tank


Age 12 years minimum. Must have 1-year prior experience and will be subject to ROOKIE RULE

All ROOKIE’s will have a steamer attached to their car and will start at the rear of the line up until all driver’s feel confident to allow him/her to their drawn starting position. This will be determined by a meeting of all drivers’ and with the rookie driver present along with their guardian. Driver’s that were 12 or 13 years old in 2010 in the 600 class will be allowed to race as long as they had 1 full year experience.

Stock fuel injection models allowed; only stock parts for that model allowed; no aftermarket add-ons.

Must have muffler.


Chassis must be constructed of top quality materials and must be structurally sound, whether factory built or home built. All chassis will be inspected for structural integrity.

Must have a full floor plan from front of seat to past the pedals. Must have a metal firewall (steel or aluminum) that is sealed as well as possible to protect the driver for fire or hot oil.

Bodies must be neat in appearance and can be constructed from aluminum, fiberglass, or carbon fiber. Plastic must NOT be used for any interior panels or body panels. All cars must have front and rear and nerf bars. Left side nerf bar should be constructed to protect engine as much as possible.

Car number must be a minimum of 8” high and on both sides of top wing. 8 in. numbers must be on the tail section of the front wing.

Battery must be securely fastened on the inside of the car.

Any additional weight must be lead and must be bolted in a secure fashion to the chassis only. Any lead or steel weight must be painted white and have the car number clearly and legibly marked on each piece for ID purposes.


 Nose wing can be no larger that 18in x 28in. With side boards a maximum of 8in x 21in. Top wing must be no larger that 12 sq ft. Side panels can be no larger that 54in x 24 in. Any type wing slider can be used. Centerline of wings must be within 2 in. of centerline of chassis.


 Can be torsion bar or coil over any combination of the two. Any type shock can be used. There can be no cockpit adjustable suspension components.  Wheelbase can be 58in. Minimum and 65in. Maximum. Maximum width is 65 in on any part of the car.


1998 and older engines are open. They must be normally aspirated and no larger than 637cc.

1999 and newer engines will be U6SA

All multi-motors must run RD25 right rear tire or equivalent.


Traction control of any kind is strictly forbidden. Any device that extends the factory preset rev limit for whatever make or model engine being used is strictly forbidden. All electronics must be fully accessible for technical inspection. No hidden items.


Must be powerful enough to slide rear wheels at moderate speed. Left front brake is allowed.


Must be 10in diameter maximum. Right rear can be 13 in wide maximum measured from inside of beat to bead lock.

Right rear wheel must be 3-piece aluminum or heavy gauge steel.


Can be any brand or compound on front & left & right rear.

Absolutely NO tire softening agents of any kind allowed.Wells Lions Club Racing Series - Microsprint Rules - 2011


775lbs minimum weight after race with driver. (subject to change)


May be gas or methanol only.

Top end lubricant is allowed.

Performance enhancing additives are not allowed.


Must be constructed of high impact plastic and must be designed as a fuel tank or other fuel cells such as RCI. It must be securely mounted with grade “8” bolts. Vent valve must be roll over type with check valve. All fuel lines must be of high quality and well protected from damage.

Bladder tank is highly recommended.

Wet fuel tanks will be allowed until 2012.



2011 600cc Micro Sprint Universal Engine Rules

1. Terms and conditions

a. If a change or modification to the stock engine or its parts is not included in these rules then the modification is considered legal.

b. The word “Stock” means unmodified factory original parts or components

2. Overall Engine

a. No limited production race motors allowed. Must be a production motorcycle engine, 4 cylinders, 4 stroke

b. No titanium anywhere in or on the engine unless it comes stock form manufacturer of engine on the production bike

c. Must have engine, clutch, and transmission all in one unit & must be chain driven.

3. Bore and stroke

a. 600cc Maximum displacement for an engine model that was new in 2006 or newer. Older engines maximum displacement is 637cc.  Engine model is defined as a manufacturer redesign of overall engine. See specification list. 

b. No strokers or de-stroked engines

4. Head & Cams

a. NO PORTING of intake or exhaust runners. 

1. Valve jobs, valve grinding, valve seating, valve seal modification and valve seat cutting are allowed.

2. Valve seat inserts may be reworked or replaced with any seat of original dimensions. Any dimensional  hickness of the stock inserts may not be increased. Valve seats can be ground with multiple angles. Blending of the valve seat into the head is permitted but cannot extend more than ¼” into the aluminum head measured from where the seat meets the head.

b. OEM Head only.

c. Cam may not have a higher lift than the stock factory cam. (duration is open)

d. Valves can not be larger in diameter than factory stock valves.

5. Bottom End

a. No machining to remove weight from the crack (balancing of the crank is ok)(no after-market cranks)(no lightweight cranks)

b. No after-market connecting rods. Must use stock factory connecting rods. 

1. After-market rod bolts may be used.

c. No dry sump systems are allowed unless it comes from the motorcycle manufacturer as original equipment.

6. Clutch/Transmission

a. No removal of clutch.

1. Clutch must remain operational

b. No modification to the stock transmission gears, no close-ratio gears or nonstandard gear-rations. All gears must remain in transmission, no removing any gears.

7. Ignition

a. No aftermarket ignition systems; must use factory stock or factory racing ECU, 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. Stock Rev Limiter must remain intact at all times (Ex: no switched or gear specific limiters). 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. May use different year ignitions from same manufacturer as long as stock rev limit or engine (not ignition) is retained.

d. No aftermarket coils

e. No gear position sensor may be used. The sensor may be in place on the engine, but can not have any wires connect to it. Gear position wire from ECU may not be switchable.

f. No traction control deviceWells Lions Club Racing Series - Microsprint Rules - 2011

g. No more than one ECY box present in or on car.

h. A 50 rpm over rev tolerance for the purpose of tech inspection is acceptable. (Note: this does not mean you can turn up the rpms in any ECU by any amount)

8. Air Induction System

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

b. Any carburetors may be used on any engine, regardless of year of engine. Note: Switching to carburetors on engines that came with fuel injection usually increases the rev limiter due to the removal of the injectors as the ECU cuts fuel to limit rpm’s before it cuts the ignition. A reflash of the ECU will be required if using carburetors in order to comply with the rev limit rule 7. a.

c. If the engine did not come from the factory with fuel injection, fuel injection may not be used.

d. No after market throttle bodies. After market conversions allowed.

e. Mechanical Fuel Injection (MFI) can be used.

9. Exhaust

a. A muffler must be used with the exhaust system that will keep noise levels within individual track limits. 

10. Charging system

a. No removing the charging system, it must remain in complete working order, no factory racing charging systems.

11. 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.

12. Fuel

a. No fuels other than alcohol, gasoline, and/or top lube. Non flammable top lube only, no exotic fuel additives, no oxidizers, no fuel enhancer top lube.  If you do not meet these requirements, you will be required to run a Hoosier RD25 or Equivalent Right Rear Tire.


Helmet must be SNELL DOT 05 or newer. Must be MA or SA RATED. Must also be FULL face with eye protection.

Following Safety Items are strongly recommended: Name Brand Flame Retardant Uniform, 5 Point racing style Harness, Racing Style Shoes, Arm Restraint’s, Flame Retardant Glove’s and a Neck Brace or Helmet Restraint. Cage Net Recommended.

Must have master electrical shutoff clearly marked.