BSA 'Sloper' motorcycle, 1927.
© Science Museum / Science & Society Picture Library
This 500cc single-cylinder petrol vehicle made by BSA (Birmingham Small Arms) Cycles Ltd of Small Heath, Birmingham, represents an important stage in the technical development of the motorcycle. Earlier machines had a higher centre of gravity, were les stable and generally noisier than the Sloper. It had a 'saddle tank', low build, and improved comfort and road holding, a basic configuration that was to influence the design of the motorcycle for 30 years. Although the Sloper was an attractive design aesthetically, performance was sluggish and the machines were difficult to steer.