BSA B50 frame, it was a replacement frame and it is unstamped. The frame is good and straight. Please look at the photos as they form part of the description.
1958-73 BSA C15 B25 B44 B50 Surflex SINTERBRONZE Rennkupplungs-Set S1992
BSA B50 Ölpumpe
BSA B50 Innensteuerdeckel
BSA B50 Steuerzeitenabdeckung
Triumph TR25W 250 BSA B25 Nockenwelle
BSA B44 C15 B25 Top Yoke 40-5114 H2