1939 BSA B12 Sports
Country: Great Britain
Engine: Air-cooled single-cylinder 4-stroke
Ignition: Lucas magneto
Power rating: 12hp
Bore x Stroke: 63 x 80mm
Displacement: 249cc
Valves: Overhead, pushrod-activated
Fuel System: Single Amal, 25/32-inch bore carburetor
Transmission: 4-speed
Suspension: Front girder forks, rigid rear
Brakes: Front and rear drum
Weight: 325lb.
BSA’s 250s were available in two versions, Standard with side valve motors, and Sports with overhead valves. BSA continued this Sports model’s basic design on to the later B31 350cc and B33 500cc models and, of course, on the legendary Gold Star.