BSA B50MX Parts & Spares
The B50 is the last and largest of BSA's unit singles, a 500 built for competition and sold as the B50MX, the B50T and the B50SS. It outlived the factory: the engine went on to power the CCM motocrossers, which is why parts for the two are hunted together.
Obsolete Bike Parts holds over 40 B50 line items, with the internals a rebuild actually stops for.
B50MX, B50T and B50SS
All three share the 500 unit engine and most of its internals. Frames, tanks, exhaust routing and gearing differ, and the MX machines carry competition-specific parts that the road bikes never had. Some components also carry back to the smaller B25 and the C25.
What we stock
- Top end: pistons in standard and oversize, camshafts with cam wheel, pushrods
- Bottom end and lubrication: oil pumps complete, gasket, oil seal and thrust washer sets
- Transmission: mainshaft gears, clutch centres, alloy clutch chainwheels, primary covers
- Chassis and exhaust: fork stanchions in high tensile steel, upper side silencers, stainless screw kits
The CCM connection
Where an item suits both, we list it under each. If you are working on a CCM, the CCM listings and these overlap heavily, and the B50 pages are worth checking as well.