Gasket, primary cover, BSA M20 B31 M21 1939-55

Gasket, primary cover for  BSA 1939-1943 WD M20, C10 C11 B21 B23 B24 B25 B26 M21 M22 M23 M24; 1947  B31 B32 B33 B34 Tele fork,  M20 M21 girder fork, C10 C11 tele fork; 1948-55 M20 M21 M33 rigid and spring, M21 AA model
Original part number
66-7514 - front chain case joint washer (cork)