The BSA C11 is a British motorcycle made by Birmingham Small Arms at its factory in Armoury Road, Small Heath, Birmingham, between 1939 and 1956. The actor Steve McQueen owned a 1951 example.
BSA C11 at a glance
| Maker | Birmingham Small Arms Company, Armoury Road, Small Heath |
|---|---|
| Production | 1939–1956 |
| Engine | 249 cc overhead-valve single |
| Construction | pre-unit |
| Developed from | side-valve BSA C10 |
| 1951 update | plunger rear suspension |
| Military version | W-C11, 530 ordered by India in 1940 |
| Gearbox fix | C11G, three-speed rigid or four-speed plunger |
| Replaced by | BSA C12 in 1956 |
Based on one source, the English Wikipedia article on the C11. No free photographs of the C11 were found, so the page runs without pictures.
History of the BSA C11
The C11 was a pre-unit single developed before the Second World War from the side-valve C10. Fitted with overhead valves and displacing 249 cc, it was launched in 1939 and continued to be developed into the 1950s. The frame was improved in 1951 when BSA added plunger rear suspension.
The British armed forces used only a few C11s as lightweight transport, having chosen the BSA M20 instead, but in 1940 the Office of the High Commission of India ordered 530 machines in military specification. The war modifications were a rear carrier over the mudguard, an additional air filter on the fuel tank and a magneto-dynamo in place of the coil.
Problems with the gearbox were dealt with by the C11G, which came 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.
Steve McQueen’s 1951 C11 was painted British racing green, with a chrome tank carrying green and gold accents and chrome wheels with green spokes. After his death his wife Barbara kept the machine for many years before it was sold at auction.
From 1956 the C11 was replaced by the BSA C12, which used the same 249 cc overhead-valve engine in a modern frame with good suspension, more efficient brakes and a more comfortable seat. A number of engine changes also made it more reliable than the C11. The C12 was in turn replaced by the BSA C15 in 1958.
Design and features
- Pre-unit overhead-valve single: a 249 cc engine developed from the side-valve C10 before the war.
- Plunger rear suspension from 1951: a more comfortable frame than the rigid original.
- C11G gearbox fix: the model that cured the gearbox troubles and became a favourite commuter.
- Star quality: the 1951 C11 owned by Steve McQueen, kept by his family after his death.
BSA C11 versions
- C11 (1939): the original 249 cc overhead-valve single.
- W-C11 (1940): military specification for the Indian order, with a rear carrier, extra air filter and magneto-dynamo.
- C11G: three-speed with a rigid frame or four-speed with a plunger frame, and better front brakes.
- C12 (1956–1958): the same engine in a modern frame, with better suspension, brakes and reliability.
The C11 was replaced by the C12 and then by the unit-construction C15; the army chose the M20 instead of it. More models are in the BSA collection.
Video: 1951 BSA 250 C11
Video by Aceclassics100 on YouTube.
Sources
- BSA C11, English Wikipedia: development, military version, C11G, C12
