BSA 'Golden Flash' motorcycle, 1953.
© Science Museum / Science & Society Picture Library
A vertical twin-cylinder motorcycle, made by BSA (Birmingham Small Arms) Cycles Ltd at their Small Heath factory in Birmingham, West Midlands. This was an advanced form of high performance motorcycle capable of speeds approaching 100 mph. The engine has an overhead-valve and vertical twin-cylinder, with the valve gear operated from a single camshaft. It weighs approximately 448 pounds.