BSA A7 Parts & Spares
The A7 is the 500 pre-unit twin that BSA built either side of a complete redesign, which is the first thing to establish before ordering anything for one. The earliest long-stroke engines stand on their own. The later A7 was reworked around the same architecture as the 650, and from that point on a great deal is shared between the two capacities.
Obsolete Bike Parts carries close to eighty A7 items and will tell you plainly when an A10 part does the same job, which is more often than the model listings suggest.
Early engine or late?
A7s built in the first years after the war use the original long-stroke engine, and its internals are not interchangeable with what came afterwards. The redesigned engine of the early fifties follows the A10 layout, and the Shooting Star that joined the range added an alloy cylinder head and a higher state of tune. Frames moved from rigid and plunger to swinging arm across the same period. Engine and frame numbers separate all of this in one go.
Stock on this page
- Engine: 500 pistons and rings, valves and guides, gaskets, timing parts
- Gearbox: separate box internals, selector components, sprockets
- Clutch and primary: plates, springs, chaincase components
- Electrics: magneto and dynamo parts, lighting, switchgear, wiring
- Chassis: brakes, fork and suspension parts, cables, fasteners
Shared with the A10
Many components suit both pre-unit twins, and where that is the case we would rather point you at the shelf that has stock than at the one with the right model name on it. Ask us to confirm before you buy two of something you only need once, or before you give up on a part that is listed under the 650.