he largest supplier of proprietary motorcycle engines in the world, J.
A. Prestwich & Co (aka JAP), decided to go racing with something unique
in 1922.
In a matter of weeks, a small team headed by Val Page, aided by Herbert
Le Vack, had produced a radical new design - the first British
double-overhead-camshaft motorcycle racing engine.
With this amazingly advanced engine fitted to a New Imperial frame, Le
Vack stunned his competitors at the 1922 Isle of Man TT. From then on
the engine and its successors proved invincible - breaking numerous
National and World Records over a four-year period. Yet the subsequent
world recession, and a world war, consigned these achievements to memory
and eventually bestowed upon them an almost mythological status. JAP's
engineering archives were discarded, and the handful of engines made
might well have been lost too had it not been for a series of
enthusiasts.
In Le Vack's Legacy, Brian Thorby traces the fortunes of the small
number of JAP racing engines and parts that have wandered Europe for
nearly a century. Much has been written and illustrated about JAP ohv
Speedway and V-twin engines, but almost nothing about their
unconventional double-overhead-camshaft brothers - until now. This
authoritative new account finally puts aside the myths and sets the
record straight.
