The Classic Motorcycle
Early Flashes had a polished aluminium case containing the crankshaft shock absorber, the duplex primary chain and its adjustable tensioner. The clutch had six springs and five plain, five lined plates. The gearbox was bolted to the engine, making this a semi-unit construction arrangement.
Standardising with the swinging arm frame meant the gearbox was located independently. However, the internals remained the same as the ’box was a sturdy design with no inherent problems. Marked ‘STD’, the ratios were common to other A- and B-series models.
A slotted mounting arrangement allowed for primary chain adjustment. The revised layout also required a different primary chaincase. With so much in common with other BSA models, parts availability is good. Modern clutch plates are more effective and any other transmission items should be readily available.