Frame / engine numbers

[topher]

Morning all. I have a question about an A10 I'm rebuilding, '50 plunger.
The frame no. starts ZA7S (?5) and the engine ZA10. Is that correct or should they both be ZA10xx to be true?
Cheers

[Greenfield]

Hi, as far as I can see, the frame on a 1950 plunger should be ZA7S6001 on and the engine ZA10101 on. Does that work?

[idie]

I don't think BSA did matching engine and frame numbers until the A65s

[Ian C]

BSA frame numbers were stamped with the designation of the lower capacity model using same frame for most of the time. Exceptions being during WW2, all WM20s left Factory with matching engine/frame numbers. For A10s, AFAIK the frame numbers of the Rocket Goldstars were stamped A10, but all other versions were stamped A7.
BSA began stamping matching engine and frame numbers for all models around 1966. HTH

[Pete Gill]

I don't think BSA did matching engine and frame numbers until the A65s

Early A65s had frame numbers beginning A50

[topher]

Thanks for all the replies guys, good info