BSA's first production parallel twin, the A7 was extensively revised for 1951 along the lines of the newly introduced Bert Hopwood-designed A10 650 and continued fundamentally unchanged until 1954, when the introduction of a new duplex frame for the BSA twins range meant that the original bolted-up gearbox had to go. Otherwise the engine remained much as before, though the new sports 500 - the A7 Shooting Star - featured an alloy cylinder head and detachable inlet manifold. With 32bhp on tap, the sporting A7SS was good for a top speed in excess of 90mph. Production ceased with the introduction of the unitary construction A50 in 1962. This example benefits from an engine and gearbox rebuild undertaken by marque specialists, SRM Engineering five years ago (see bills on file), since when it has covered only 1,000-or-so miles. Upgraded with the later BSA-Triumph twin-leading-shoe front brake, the machine is offered with MoT to September 2011 and Swansea V5.