J.A.P (J.A. Prestwich) of Tottenham, London, produced a wide range of engines for many different applications. Motorcycle engines for standard, sports, and racing use were available, and many common manufacturers used them. Royal Enfield used the v twin engine from 1912 until 1919 when they developed their own engine (which did look very similar to JAP), Morgan 3 wheelers, Brough Superior, and Zenith were just a few more.
I even have an early 500cc single engine that has been converted to a marine application. A brass water jacket has been fitted around the cylinder barrel, and nicely done too, and it has been converted to a hand lever start. I always thought that it would look exceptional fitted into a frame with a polished brass fuel tank and radiator. You never can tell……
Anyway this is a 22 page book produced in 1933 to cover the engines to date that had been manufactured. It has an excellent description of the early oiling systems, includes valve timings, ignition timings and tappet clearances. The sort of information that is never that easy to find when you really need it.
Click on the front cover below to see the complete manual.
It is a 2.37M PDF and you will need Adobe Acrobat Reader to view it.
1917 Advertisemnt for the 5hp V Twin Engine.
Click here to see a copy of the 1927 J.A.P Catalogue