The class is loosely based on the old CIK Formula C with some restrictions and modifications. Karts conforming to the Formula 125 ICC regulations may compete in this class at the class weight of 180kgs and to their class regulations. The British Superkart Association offers the only National Championship for this class in the UK.
Chassis:
Must confirm to current MSA Technical Regulations and MSA Safety Regulations. All chassis main parts must be firmly securely together on to the chassis frame. Flexible connections are only authorised for the conventional steering knuckle support, and for the steering system . All other devices with the function of one, two or three dimensional joints are forbidden. The chassis frame is the central and main supporting element of the entire vehicle. It must have the necessary strength in order to be able to absorb the loads which are produced when the vehicle is in motion. Any hydraulic, pneumatic or elastomeric elements for damping chassis oscillation are forbidden.
Bodywork:
Either Short or Long Circuit style bodywork must be fitted to the kart at all times. A bubble conforming to Blue Book Section N.14 and figure N7 is permitted as an alternative to a Nassau panel.
Engines:
Any 125cc engine previously or currently eligible for CIK Formula C (single cylinder engine with reed-valve or rotary-valve intake, air cooled by natural air flow or water cooled, with single circuit *, registered by the CIK-FIA before March 2000 and valid, or water cooled single cylinder engine with reed-valve intake, with single circuit *, homologated by the CIK-FIA in ICC) plus any engine registered with the MSA for the pre 2004 National 125 class as listed in Appendix 2 of the MSA Kart Race Yearbook or any ICC homologated engine with a cassette gearbox option from the original manufacturer.
* An additional inner circuit for the normal functioning of a thermostat is allowed.
Active power valves are not permitted but may be used if locked in position
Tuning Regulations:
Modifications to the engine are allowed, providing the following are not varied.
a) Stroke
b) Bore (outside maximum limits)
c) Connecting rod centre line (magnetic material only)
d) Crankshaft must be on the manufacturers parts list
e) External appearance of the engine other than carburettor, ignition system, carburettor rubber mounting, clutch cover, engine mounting points and reed block where applicable. (The addition of a fuel pulse pump adapter is permitted.)
f) Number of carburetors (1 only). The material magnesium is not permitted.
g) All systems of injection and/or spraying of products other than permitted fuel are forbidden.
h) No form of electronic carburetion system
i) No form of variable ignition that may be adjusted whilst the kart is in motion
Noise Control:
See regulations T1.1 to 1.10 above.
Transmission:
Maximum of six gears. Gear ratios can be changed.
Brakes:
Brakes to MSA Blue Book section N.14.7
Wheels and Tyres:
5" or 6" diameter wheels and tyres with a maximum tyre size width of 7.1" rears and 5.5” fronts may be used.
It is not permitted to mix 5” and 6” tyres on the same axle line
Weight:
Long Circuit Style Bodywork - 190kgs minimum.
Short Circuit Style Bodywork - 180kgs minimum.
Plates:
Blue number plates with white numbers.
Age:
The class is open to any driver aged 16 or over on long or short circuits. Novice drivers are permitted on both long (closed to club and National B events only) and short circuits.