Print Page - Frame / engine numbers

Title: Frame / engine numbers
Post by: topher on 13 Sep, 2023, 07:19

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

Title: Re: Frame / engine numbers
Post by: Greenfield on 13 Sep, 2023, 07:30

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?

Title: Re: Frame / engine numbers
Post by: idie on 13 Sep, 2023, 07:55

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

Title: Re: Frame / engine numbers
Post by: Ian C on 13 Sep, 2023, 13:29

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

Title: Re: Frame / engine numbers
Post by: Pete Gill on 13 Sep, 2023, 17:59

Quote from: idie on 13 Sep, 2023, 07:55
I don't think BSA did matching engine and frame numbers until the A65s

Early A65s had frame numbers beginning A50

Title: Re: Frame / engine numbers
Post by: topher on 14 Sep, 2023, 21:46

Thanks for all the replies guys, good info

BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: topher on 13 Sep, 2023, 07:19