BSA M20 engine and frame numbers for 1940 should not match unless there was an unusual coincidence when the bike was built. Even though the M20 engine and frame numbers started from WM20-101 for that year, the M21 and M23 models also used the same sequence of numbers for their frames but different numbers for their engines. I suppose that the honest answer to your question is....possibly, but highly unlikely. Beezageezauk.
#15221 - 09/10/063:27 amRe: 1940s BSA Frame and Engine Numbers.
Joined: Sep 2006 Posts: 36CanadaBike
BritBike Forum member
I am restoring my 1951 BSA Alloy Clipper 500 single, it's BB34A247 HC with the alloy barrel similar to gold stars with their iron barrels.
Given the above page I now know its a 1954 but no big surprise I have had it since it was 7 years old having bought it off the race track. Its been stripped of stock tank, seat, fenders, bars and lights and I want to get as much of the near original similar looking parts as possible without having the fortune to get it 100% authentic.
metaphors be with you
#15224 - 09/13/065:04 amRe: 1940s BSA Frame and Engine Numbers.