History

1958 saw the beginning of a completely new departure from the usual engine/transmission design with the introduction of unit construction machine in place of the 250cc C12. The first of this new breed of motorcycle, the 250cc C15 Star, was an instant success. It had a clean, uncluttered appearance and provided reliable and economical transport.

This change from the old arrangement of separate gear box and engine was also accompanied by a redesigned frame which proved to be much better than that of the C12. The 250cc was based on the Triumph Tiger Cub 200cc, with a vertical cylinder and an up-to-date styling. It proved a success in many ways, but especially as this was the largest capacity solo machine that a learner rider in the UK could have until they had passed their driving test. This may have accounted for the reputation of the exploding gearbox, poor valve gear, weak big-end and a nasty clutch, which turned up when they were thrashed.

In 1961 the Super Sports model (SS80) was added to the range. This had a tuned engine with roller big-ends, and lower handle bars to give a sleeker look, but it could still blow up the gearbox.

In 1965 the distributor was moved to the right hand side cover which gave an enhanced appearance and was adopted by the whole range of BSA bikes.

During 1967 the 250cc C15 was replaced by the B25 Starfire and C25 Barracuda models, which featured a quickly detachable rear wheel and 12 volt lighting. Although this was an improvement on the C15 engine with tougher internals and castings, it was susceptible because of it’s higher state of tune and having car type big-end shell bearings to big-end failure.

Trials and Scrambles versions were available from 1959 and became very popular with riders, due to their power/weight ratio, handling qualities, high torque and reliability.