SL, the initials of Sutton-Lewis, was a motorcycle built during 1924.
A prototype was constructed with racy lines. It had a 348cc twin-port three-valve ohv single-cylinder engine, with a single inlet and two exhaust valves. This was coupled to a close-ratio Sturmey-Archer gearbox and fitted into a low duplex frame with frontal Scott telescopic forks.
Production was planned for the following year, but nothing came of it.