BSA Sloper

The BSA Sloper, formally the BSA S-Series, was a series of motorcycles produced by the Birmingham Small Arms Company of Birmingham, England, from 1927 to 1935. Launched in 1927, it featured a slanted 493 cc overhead valve engine and a saddle tank that allowed a low seating position, improving the centre of gravity and handling. The S designation covered all BSA engines of the same bore and stroke, whether sloped or vertical and overhead valve or side valve, and each model carried the two digits of its year, so the S31 was the 1931 range. Many riders regarded it as one of the smoothest and quietest sporting 500 cc machines, and from 1932 all had a four-speed gearbox.