The BSA M22 Sports was a 496 cc overhead-valve single in the BSA M series, introduced in 1937. The M series was a range of pre-unit single-cylinder side-valve and overhead-valve four-strokes made at Small Heath from the 1930s to the 1960s, mostly designed by Val Page in 1936 for the 1937 model year.
BSA M22 at a glance
| Maker | Birmingham Small Arms Company, Armory Road, Small Heath |
|---|---|
| Introduced | 1937 |
| Production ended | 1939 |
| Engine | 496 cc overhead-valve single |
| Bore × stroke | 82 mm × 94 mm |
| Shared dimensions with | M20 and M23 |
| Optional | twin-port head with high-level exhausts |
| Twin-port models built | around 300 |
| Designer of the range | Val Page, 1936 |
Based on one source, the English Wikipedia article on the M series, which covers the M22 in a short section; the page is therefore short. No free photographs were found.
History of the BSA M22
In 1936 BSA decided its range needed a revamp to sell more in the improving world economy, and hired Val Page to update it. Page scrapped the whole range except the V-twins and designed a completely new line of single-cylinder motorcycles. Engines now used dry sumps with the magdyno behind the cylinder, and the new frames were made entirely of tubes rather than the cast backbone used previously. Models took a B prefix for the lightweights and an M for the heavyweights.
The 496 cc overhead-valve M22 Sports was introduced in 1937. It shared its 82 mm by 94 mm bore and stroke with the M20 and the M23, and a twin-port head was available as an option; the twin-port versions were fitted with high-level exhausts, and around 300 of them were made. Production stopped in 1939.
The M22 sat between the side-valve tourers and the sporting M23 Empire Star, which was the top of the BSA single range and which Wal Handley rode at Brooklands in 1937 at a fastest lap of 107.57 mph, earning a Gold Star badge and prompting the all-alloy M24 Gold Star of 1938.
Design and features
- Overhead-valve M-series single: 496 cc with an 82 mm by 94 mm bore and stroke shared with the M20 and M23.
- Twin-port option: a twin-port head with high-level exhausts, of which around 300 were built.
- Part of Val Page’s 1937 range: dry-sump engines, magdyno behind the cylinder and all-tube frames.
- Short production: built from 1937 to 1939 only, before the war ended civilian development.
BSA M22 versions
- M22 Sports (1937–1939): the single-port overhead-valve model.
- M22 twin-port: high-level exhausts and a twin-port head, around 300 made.
The M22 was part of the M20 family, and its stablemate the M23 Empire Star led to the Gold Star. More models are in the BSA collection.
Sources
- BSA M series, English Wikipedia: M22, M-series background, related models
