BSA C11

The BSA C11 is a British motorcycle manufactured by Birmingham Small Arms Company (BSA) at their factory in Armoury Road, Small Heath, Birmingham, between 1939 and 1956. Actor Steve McQueen owned a 1951 BSA C11.

Development

The BSA C11 was a pre-unit single-cylinder developed before the Second World War from the sidevalve C10. Fitted with overhead valves and displacing 249cc, the C11 was launched in 1939 and continued to be developed into the 1950s. The C11 frame was improved in 1951 when BSA added plunger rear suspension.

Military W-C11

Although British armed forces only used a few BSA C11s as lightweight transport (having selected instead the BSA M20) in 1940 530 C11s were ordered in military specification by the Office of the High Commission of India. Modifications for war use included a rear carrier over the mudguard, an additional air filter on the fuel tank and a mag dyno in place of the coil.

BSA C11G

Problems with the gearboxes were addressed by the model C11G, which was available either with a three speed gearbox and a rigid frame or with a four speed gearbox in the plunger frame. The C11G also had improved front brakes and became popular as a post war commuter motorcycle.