twin identification

[Nehroom]

just bought a bsa a7 plunger but the frame and engine number suggest its a star twin both engine and frame number start with BA7S so what do you think
Steve

[JulianS]

The S in a frame number means plunger frame, used on the A7, A7 Star twin and A10 Golden Flash.

S in an A7 engine number means Star Twin.

[Nehroom]

Thanks for clearing that up does anyone know what the correct tank badge is as I'm finding it difficult to know what to put on the petrol tank

[EDDIE SIMPSON]

unfortunately its dark and my tank looks worse than it actually is. the chrome is peeling off.
i think the tank is different from standard for the star twin tank badges to fit.
i have the star twin tank but not the bike. my bsa is a standard a7.

[Nehroom]

many thanks for the photos I've seen that badge on a few bikes on the Internet so I will try and order a pair
Steve

[cranwell]

Hi Steve.
That pressed tin 'Star-Twin' badge was only used up to the 1952 year models.  I posted an in depth reply on your wanted page. Regards, Pete