Well not so much ‘surface,’ as published for the first time. Quite a few years ago a roll of film, which had been found in the street, was handed in to the police in Wolverhampton. The roll was of over 700 microfilmed JAP drawings which had perhaps been dumped after Villiers took over JAPs and moved the remnants of the JAP Tottenham (London) factory to Wolverhampton.

Not being claimed or an owner found, and rather than being destroyed, the film was given to a friend of ours who allowed the Vintage Motor Cycle Club and the Morgan Three-Wheeler Club to copy them. The MTWC made digital copies and a copy was given to Loose Fillings some years ago.

The first set of three drawings published are of the 8/45 KTOR and JTOR crankcases of 1924 or thereabouts, probably with the later addition of ribs to the drive-side crankcase. There should be a timing cover for a single platform magneto but we have not found it yet. It may be that the drawing was lost when a new drawing was done for the 8/80 in 1936.

Future uploads will include the 1936 8/80 996cc JAP and the postwar Mk1 1098cc JAP used by Coopers. As well as crankcases there are cylinder barrel and head drawings of various types but no small parts –  the collection is almost exclusively of drawings for moulding and machining of castings in iron and aluminium.

As well as twin-cylinder engine drawings there are many of the speedway 500 engine which will also be published. Note that the drawing number is the same as the JAP part number

So, watch this space, and here is the first being the 1924  and onwards crankcase for the JTOR, KTOR and probably the water cooled LTOW. Later, these drawings were amended for the 8/80 and in due course the 8/80 timing cover was amended in 1949 to suit the pump used for the dry-sump engine.

If you want higher resolution files, you can download pdfs from JAP DRAWINGS in the menu across the top of the page.

Image (561) JAP7405Above: Drawing 7405


Image (560) JAP7406Above: Drawing 7406


Image (559) JAP740X

Above: Drawing 7439 for chain driven magneto


Here’s a list of the available motorcycle-type engine drawings which will eventually be published:


Jap DwgList_Page_1

Jap DwgList_Page_2

Jap DwgList_Page_3

Jap DwgList_Page_4

14 thoughts on “JAP DRAWINGS SURFACE”

  1. Unfortunately I haven’t got round to publishing more and there are nearlyl 700 which have to be uploaded one by one . The VMCC library has a full set. Or let me know what you need in particular and I will email to you.


  2. I’m really interested in those that relate to the V-twin engines, but I couldn’t specify the particular drawings offhand, I know it’s a pain and I am very grateful for your reply but would in be possible to use a service such as WeTransfer, (2Gb at a time for free), or similar, to undertake a bulk transfer I could download?


  3. You will have to be specific Tom. The relevant drawings are all on the list so let me know which you want and I’ll do my best.


  4. Hello, I don’t have the drawings you asked for and I am interested to know where your list came from. I do have a 1930 head which uses the 7379 and 7397 patterns which must be the original KTOR patterns. I will extract the drawing from its archive and post it if I can remember how :). I don’t recognize the 10XX numbers and suspect they must be early general arrangement drawings.


  5. Sorry, I was missing page 1 in my print-out. I assume you mean 10128, 10129 etc and should be able to find them now. Unfortunately the computer image file names don’t match the handwritten list which was prepared from the microfilm by the VMCC.


  6. Yes,
    10128 and 10129
    Additionally please post also 11941and 11942, that would make full set of KTOR drawings from your list.


  7. Hello,

    gsjenergia requested the full KTOR drawings list:
    and later 10128, 10129 and 11941 and 11942.

    Would it be possible to send me the drawings on that list as well? It would be very much appreciated!


  8. I am really sorry, but at the moment I don’t have easy access to these and the list published came from the Vintage Motor Cycle Club (UK). For the moment you will have to contact them for copies which they will do for a fee.


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