Regulations

Classic 50cc Regulations

ALL machines must comply with ACU Standing Regulations.

This is Classic orientated road racing for machines of the style and type used up to the cut off date of 1983 when the 50cc GP ceased to be a class.

The Technical Committee will respond to any query within one week, and the question and outcome will be posted on the club forum.

It is the rider's responsibility to make sure that his machine is presented in a clean, tidy and safe condition at each meeting with particular attention to safety critical components such as brakes, for example when engines have been upgraded in existing chassis.

It is on the onus of the rider to check with the Technical Committee that the machine meets the criteria set out below.

Frame:

Steel tube, Aluminium Monocoque or plate types are allowed. No modern or twin-spar types allowed. NO upside down forks are allowed.

Brakes:

Twin pot/piston Disc Brakes are permitted but must be of period appearance, no modern wavy discs allowed. Maximum diameter of disc is 240mm.

Wheels:

17" minimum in diameter with WM1 or 1.6 maximum rim widths.

Tyres:

Maximum width 80mm when fitted. Tyre warmers, slicks, and cut slicks are not permitted. Treaded tyres including wets can be used.

Engines:

Air and Water-cooled, manual gearbox with a minimum of 3 gears and a maximum of six. Swept volume of 50cc, with a maximum over volume tolerance of 5% for UNPLATED BORES ONLY (i.e. 52.5cc). Plated bores of any type CANNOT use the 5% oversize tolerance (ie. 50cc max). This also applies to 4-stroke machines.

Machines with an engine capacity over this tolerance may be allowed to race but this must be agreed with the event organizers and race director prior to commencing the race. Riders using this rule must register with the club technical committee and organizers prior to the event.

Should any machine outside the 5% tolerance be entered in a 50cc race this must be registered with the clubs technical committee in writing and will not score any club championship points. THIS IS CRUCIALLY IMPORTANT due to insurance implications.

Carburettor can be any type, but electronic power jets are not allowed. Ignition can be any type, but modern looking components should be hidden.

Race Numbers:

Black numbers on white backgrounds.

Bodywork:

Any bodywork representative of the classic pre-1983 style period can be used. Any carbon fibre must be painted in a solid colour.

ALL ENTRANTS FOR THIS CLASS MUST PROVIDE EVIDENCE OF ELIGIBILITY USING THE SPECIFIED FORM

As with rain lights, brake lever guards must be fitted if machine is in a mixed class.