BSA J 12, 500 cc (1934).
BSA motorcycles were made by the Birmingham Small Arms Company Limited (BSA), which was a major British industrial combine, a group of businesses manufacturing military and sporting firearms; bicycles; motorcycles; cars; buses and bodies; steel; iron castings; hand, power, and machine tools; coal cleaning and handling plants; sintered metals; and hard chrome process.
A government-organised rescue operation in 1973 led to the takeover of BSA-Triumph motorcycle operations by Norton-Villiers, later known as Norton Villiers Triumph.
At its peak, BSA (including Triumph) was the largest motorcycle producer in the world. In the late 1950s and early 1960s poor management and failure to develop new products in the motorcycle division led to a dramatic decline of sales to its major USA market. The management had failed to appreciate the importance of the resurgent Japanese motorcycle industry, leading to problems for the entire BSA group.
When Norton Villiers Triumph was liquidated in 1978, the rights to use the brand name of BSA were purchased by a new business, the B.S.A. Company.