BSA B50 Parts & Spares
The B50 was the last big single BSA built at Small Heath: a 499cc unit-construction engine in the oil-in-frame chassis of the early seventies. It came as a road bike, a trail bike and a motocrosser, and it later lived on in the CCM machines that grew out of it. That long afterlife means the engine is well understood, but it also means many B50s have been modified along the way.
Obsolete Bike Parts carries B50 engine, transmission and chassis parts in original, NOS and reproduction form. Every order is packed in the Netherlands and shipped worldwide.
SS, T or MX?
The road-going B50SS, the B50T trail model and the B50MX competition bike share the basic engine, but they differ in tuning, exhaust, gearing, electrics and a lot of cycle parts. The MX in particular was built for competition and many of its parts are specific to it. The B50 engine also grew out of the B44, so some components are shared with the 441 singles and many are not. Check the engine prefix before you order.
What we hold for the B50
- Engine: pistons and rings, valves and guides, gaskets, oil pump and timing parts
- Clutch and gearbox: plates, springs and gearbox components
- Electrics: ignition and charging parts, switchgear and lighting
- Frame and cycle parts: oil-in-frame fittings, brakes, cables and fasteners
- Fuel and exhaust: carburettor service parts and exhaust fittings
Road bike or racer?
Let us know which version you have and what it is being built for. The right part for a road B50 is not always right for an MX, and the reverse is just as true. Your engine and frame numbers help us check.