Getting it right

Designed by Val Page, Herbert Parker and David Munro, the BSA A7 was the first of BSA’s twin-cylinder motorcycles. It was ready for launch in 1939 but the outbreak of WWII delayed the launch until September 1946 after hostilities had ended. The very first A7 off the production line was flown to Paris for the first motorcycle show after the end of the war and the public’s reaction was favourable – demand was high for simple, affordable transport. The 495cc twin-cylinder engine produced 26bhp and was capable of 85mph. The BSA A7 parallel twin essentially followed Triumph lines: 360-degree crankshaft, vertically split crankcase and cast-iron cylinder barrel and head; however, it employed a single camshaft rather than the Triumph’s double. Overall, the machine seemed slightly derivative and a little unresolved.
Enter Bert Hopwood, one of the Britain’s most creative designers, responsible for the Norton Dominator (Lot 2) and the BSA Rocket 3/Triumph Trident (refer Lot 10A). One of Hopwood’s first tasks was to extensively revise the A7 engine along the lines of his newly introduced 650cc A10 Golden Flash. Launched as the BSA Star Twin, the new 1951 model featured twin carburetors and increased compression ratio.
It also had the latest design of cylinder head with authentic steel inlet and exhaust valves.
The up-rated engine was fitted to a plunger frame and finished with extra chrome as can be seen on the motorcycle offered here.