Data References for frame and engine numbers

On several occasions, I have been asked how I know my frame (or engine) is from a certain date, or for a particular model. Sometimes, I cheat. I happen to have the registration / title documents. However, it’s always good to check that the documents are correct.

As many of the motorcycles that I am interested in are pre-war, I have found that records can be either difficult, or almost impossible, to find. In some cases, the factory records were destroyed and we are left putting the pieces together from small pieces of information.

So, to save us folks some time researching, I will begin putting my saved information onto the links on this page. As with all things to do with our old motorcycles, please use the information as a guide, rather than fact.

J.A.P Engine data

Triumph motorcycle data

Sturmey-Archer gearbox data

Norton Motorcycle data