You need a Jap in your shed

This mythical shed is getting quite full, but there is always room for one more motorcycle in there and when it’s as good as this JAP then room would be made anyway.

Words and Pics: Tim Britton

In the world of performance engines, John Alfred Prestwich sort of cornered the market early on, right at the dawn of these new-fangled internal combustion engine things people were fitting into bicycle frames.


JAP did produce a motorcycle themselves for three or four years but rapidly realised their forte lay in supplying engines to others.

Being based in London rather than the Midlands kept them remarkably independent of the two wheel industry and their diversity into producing engines for cars, aeroplanes and the utility market meant they were not dependent on any one industry.

A seemingly unconnected event at High Beech, London in 1927 when the UK was shown this new dirt track sport – soon to be speedway – from Australia led to JAP becoming the engine of choice for this frenetic sport.

Using JAP’s speedway engine for a MX machine isn’t unusual, few though are as successful as Team JAP, the engine is designed for power.

Settling on 500cc engines the speedway racers needed a reliable, powerful and light engine to rocket them around a 400 yard oval for four laps a race and the JAP Speedway engine did duty well into the 1960s.

Read more in the Autumn 2019 issue of CDB – on sale now!

Enjoy more Classic Dirt Bike reading in the quarterly magazine. Click here to subscribe.