1973 BSA B50MX
1973 BSA B50MX BACKGROUND
BSA produced one of the world’s most successful 500cc singles in the Gold Star starting in 1938 and running all the way through 1963 when production ended. The entire BSA product line was being converted from non-unit construction to unit-construction and the ancient non-unit Gold Star had to go. It was replaced not by an updated version of itself, but instead by an entirely new bike with unit construction. It took a few years to bring it up to size, because the new unit-construction BSA single started out life as the 250cc C15 Starfire in 1963, then the B44 441cc Victor in 1967. It took until 1971 to punch the big single out to its final displacement of 499cc with the B50 lineup. This included the B50SS (a Street Scrambler), the B50T (Victor Trail), and the B50MX (Moto Cross) pictured here. The BSA B50s were built in 1971 and 1972, but unsold units were retitled and sold as 1973s. BSA built its last motorcycle in 1972.
1973 BSA B50MX Specifications
| Engine type Displacement Bore & Stroke Compression ratio Carburetor Ignition Horsepower output Torque output Primary drive Clutch Gearbox Final drive Battery Frame type Suspension, front Suspension, rear Brake, front Brake, rear Tire, front Tire, rear Wheelbase Length Width Height Ground Clearance Seat Height Dry Weight |
Air-cooled OHV 4-stroke single 499cc / 30.5 ci 84mm X 90mm 10.0:1 Amal 932/28 Lucas RM21 points & coil 34 hp @ 6200 rpm 28 lb/ft @ 5000 rpm Chain Multi-plate, wet 4-speed, right-foot shift Chain 12 volt Welded steel tubing, oil-in-backbone Telescopic forks, hydraulic damping Swing arm w/2 shock coil-over shocks 8-inch TLS drum, conical hub 7-inch SLS drum, conical hub 3.25″ X 18″ 3.50″ X 18″ 54.0 in / 1372mm 85.0 in / 2159mm 29.0 in / 737mm 43.5 in / 1105mm 7.0 in / 178mm 32.0 in / 813mm 310 lbs / 140.6 kg |