Bikernet Blog Search Bikernet
Ride Forever - Bikernet.com
Thursday Edition


A Touch of Motorcycle Engine History

J.A.P Prestwich, otherwise known as J.A.P.

By Sam Burns
5/9/2023


Share this story:

 
In the early years of motorcycle manufacturing, many manufacturers used bought-in engines for their motorcycles as the cost of developing engines was beyond the means of many of them. Of all the manufacturers of proprietary engines, possibly the most famous was J.A. Prestwich, otherwise known as J.A.P.
 
 
770cc JAP in the Ukraine
770cc JAP in the Ukraine


 
 
550cc single from 1922
550cc single from 1922


 
 
Without the J.A.P. engine, many British motorcycle manufacturers would never have got off the ground and, over the years, J.A.P. supplied engines to Brough Superior, Triumph, AJS, Enfield, HRD-Vincent and Zenith, as well as manufacturers in France and Germany.
 
1911 ad
1911 ad


 
 
BSA single
BSA single

 
JAP 350cc in France
JAP 350cc in France


 

The engine also saw service in cars such as the Morgan three-wheeler. The New Brough Superior Raises The Bar For Exotic Motorcycles, as well as in Formula 2 and Formula 3 racing in the 1950s.
 
1922, 250cc single
1922, 250cc single


 
 
 
600cc
600cc


 
Ad from 1923
Ad from 1923

 
 The versatility of J.A.P. engine design can be seen in their stationary engines, which have powered a wide array of industrial equipment such as generators, rotavators, water pumps, milking machines, hay lifts, and numerous machines in the agricultural industry.

1922, 350 crankcase
1922, 350 crankcase

 
1922, 350cc single
1922, 350cc single


 
1930s Speedway
1930s Speedway

 
 During World War II, the company supplied close to one-quarter of a million petrol-powered engines in addition to millions of aircraft parts.
 
1922, 550cc single
1922, 550cc single


 
JAP factory
JAP factory

 
1947, 125cc, two-stroke
1947, 125cc, two-stroke


 
 
--Sam Burns
Antique motorcycle curator
Bikernet.com™
 
1929 San Soup... 500cc
1929 San Soup... 500cc

 
The extensive list of manufacturers which employed JAP engines includes:
 
 
Acme
AJW
Aliprandi
Alldays & Onions
Ambassador
Argentre
Ariel
 
Brough racer
Brough racer

 
Atala
Austral
Automoto
 
Cotton
Cotton

 
AWD
Bown
Bücker
 
Hazelwood, check the belt...
Hazelwood, check the belt...

 
Brough-Superior
Brown
Calthorpe
Chater-Lea
Clement-Gladiator
 
La Mondiale
La Mondiale

 
Corah
Cotton
Coventry-Eagle
De-De
Dennell
DMW
Dollar
 
Matchless
Matchless

 
Dunelt
Eysink
Favor
Fusi
Ganna
Grindlay-Peerless
 
Morgan trike
Morgan trike

 
Hagon
Hazelwood
Imperia
Invicta
La Mondiale
Lady
Le Grimpeur
Lea-Francis
Majestic
 
1919 Excelsior-Henderson board-track racer
1919 Excelsior-Henderson board-track racer

 
Matchless
Meray
MGC
Morgan
New Hudson
New Imperial
New Map
Nut
 
Acme
Acme

 
OEC
OK-Supreme
Omega
Onoto
Osa-Liberty
Radior
Rex-Acme
Rover
Rovin
Royal Enfield
Royal Ruby
San Sou Pap
 
Royal Enfield
Royal Enfield

 
Simoncelli
Soyer
Sparkbrook
Stylson
Terrot
Tornax
Trump
 
1913 Alldays
1913 Alldays

 
Ultima
UT
Verlor
Vindec
Wolf
York
Zenith
 
Sources: Graces Guide
 

Chance of a lifetime. Click and join.
Chance of a lifetime. Click and join.


Share this story:



Back to In History, Special Reports


Your thoughts on this article

Your Name
Email
City
Country
v
State/Province
v
Comments
Anti-Spam Question:
Please enter the words you see in the box, in order and separated by a space. Doing so helps prevent automated programs from abusing this service.
Submit
Clear