1956 BSA M 21

Specifications
- Category
- Allround
- Displacement
- 591.0 ccm (36.06 cubic inches)
- Power
- 15.0 HP (10.9 kW) @ 4000 RPM
The 1956 BSA M 21
1956 BSA M 21 sits firmly in BSA's utility lineup, a plain-fenders workhorse built for people who needed a motorcycle to actually get somewhere rather than win trophies. This is a side-valve single doing an honest day's work: low-end pull, unhurried delivery, and a mechanical simplicity that made it a favorite for sidecar duty, farm use, and dispatch riding well into the postwar years. It rewards patient, relaxed riding rather than spirited throttle work, and owners tend to describe it less as thrilling and more as dependable in the way an old tractor is dependable. The 1956 model carried over without significant mechanical changes from the prior year — buyers comparing it to a 1955 example should focus on mileage, service history, and condition rather than spec differences. Today the 1956 BSA M 21 attracts a specific kind of buyer: someone drawn to prewar-adjacent British engineering who wants a usable, low-drama classic rather than a garage trophy. Sidecar enthusiasts and riders who appreciate mechanical honesty over performance numbers make up much of its following, with steady but unspectacular collector interest supporting values.

