petrol tank

[kev]

here is another photo

[m3bobby]

I think its from a BSA B1 of the mid 30's

heres a link to one.

http://www.andybuysbikes.com/Archive/4280.html

[cardan]

I'd be thinking closer to 1930, when both chromium and nickel plated tanks were used. There's a list of the 1930 models at Leon's BSA page (not his Leon, even if the first bike I restored and rallied was a 1930 Sloper!): http://home.planet.nl/~leonhop3/1930_e.html
You can rule out all the oil-in-sump models (like the Slopers), and from the gear change position it looks like one of the bigger models. How about the S19, a 500cc OHV, which had a nickel tank:
http://home.planet.nl/~leonhop3/1930_s19.jpg

When I restored my BSA c1980 I couldn't get kneepads to fit the protruding lugs, so I rode without. I've checked the inside of my knees, but the marks have faded...

Leon