a. Any four-stroke twin cylinder motorcycle originally sold for road use with a water cooled engine of up to 650cc, or an air cooled engine of up to 820cc, may be used provided it adheres to the 72 SAE hp power limit for the series. b. Older models may be updated with genuine parts found on a newer version of the same model and newer models may use parts from older machines as required. All parts must be used as intended for the homologated machine and in accordance with the manufacturer’s recommendations. c. All machines must comply with the machine preparation regulations as set out in the 2010 ACU handbook for road race meetings. d. In order to control costs, machine damage may be repaired in a manner agreed with the series Eligibility Officer and the Chief Technical Steward of the club. No advantage may be gained from such modifications. e. All machines must function on normal unleaded fuel available from public service stations with a maximum 102 octane in adherence with ACU standards. E85 Bio-Fuel from public outlets is permitted.

Originally Posted by Cymraeg_Atodeg (Post 2378269) http://www.zlockracing.com/new_products.html yes you can, also, try using the space bar...

Originally Posted by andrewsmith (Post 2378437) you racing minitwins or thundersport/ sprint? as that is not permitted in Minitwins

Cylinder head, camshafts, cam sprockets, crankshaft, rods, pistons, valves, cylinders and all other engine components must be as homologated. No internal engine, gearbox and clutch parts may be altered or replaced with the exception of the gear shift detent spring, the clutch friction and drive plates and the clutch springs.

Polishing and lightening of engine parts is not permitted. Balancing or gas flow modifications normally associated with individual tuning are not permitted.

Compression ratio of the engine must remain as homologated.

Camshaft timing must remain as homologated.

No other engine tuning or alteration from the homologated standard is permitted.

Originally Posted by rvracing (Post 2379040) ah yes point taken, my intention is to race in the uk minitwin class, ie bemsee, are they reliable in the valve department,??