Big bore (101mm diameter) short skirt high compression piston gives a capacity of 673cc for increased torque and horsepower. Requires cylinder liner and crankcase modifications.

Big bore (98mm diameter) short skirt high compression piston gives a capacity of 634cc for increased torque and horsepower. Requires standard liner to be bored out.

A heavy-duty rod which Moorespeed adapts to fit 1VJ and 3AJ engines. Recommended for modified engines as it gives greatly extended life to the big end.

For racing purposes only, offering great strength.

Three different stages of tune, depending on the power needed and the capacity of the engine.

Especially imported from Japan, these heavy duty bearings take more loading, and are highly recommended when the engine has been tuned for more power.

For improved engine protection, especially with modified engines, a larger capacity oil cooler is a worthwhile precaution. Our top quality oil cooler - available as 7-row or 10-row, uses standard hoses/fittings.

Large bore stainless steel header pipes and two-into-one, especially recommended for use with big bore engines, but fits all 34L, 55W, 1VJ and 3AJ engines. Can be supplied with or without boss for Lambda sensor to set fueling accurately. Complete with exhaust clamps which are laser cut from stainless steel – and do NOT bend like the originals...

We recommend using the Arrow exhaust can with these headers.

The Paris Dakar replica, made from stainless steel, and though not road legal, come with a ‘decibel insert’. Delivers more power than the original – depending on level of tune.

With its black paint finish, this is an exact replica of the original: the Yamaha heat guard fits straight on.

TwinAir washable foam filter for 1VJ or 3AJ models.

Yamaha gear sets are prone to chipping: this complete gearset of 3rd, 4th & 5th gears treated with the REM process gives approximately 40% greater contact surface than standard. Combined with crankcase modifications to feed more oil, this is the solution to achieving a long lasting gearbox for the 1VJ and 3AJ models.