BSA C10/C11/C11G/C12 250cc Piston STD 63 mm
B137/STD.29-2568Piston Assembly complete
BSA C10/C11/C12 Piston Std.
incl. rings, gudgeon pin, circlips
STD= 63mm
Piston Clearance 0.12mm or 45thou
C11 1939-55
C12 1955-58
can also be used for C10, even if they usually had a flat top