Although lacking some of the glamour of the big vee twins and later over head valve sports models the 493cc side valve single, rated at three-and-a-half horsepower and its larger brother, the 555cc four-and-a-half horsepower version, formed the mainstay of BSA's range during the twenties being equally adept as a solo machine or hitched to a sidecar. They were backed up by an extensive dealer and service network the effectiveness of which was highlighted in 1925 when BSA challenged the ACU to obtain the parts necessary to build-up one of its new 2.5hp models from its dealer network with no complete assemblies being purchased. With the parts duly purchased a machine was assembled and ridden for 100 miles, unimpressed by this, due, the ACU said, to the machine being a contemporary model, the ACU were requested to repeat the process by BSA, obtaining the components for a 1914 557cc single with the same result after three days and five hours assembling the machine!

This example of the 1928 M28 500cc single was the subject of a full restoration carried out during 2011 which has seen it returned to a beautiful condition. It is offered complete with a full acetylene lighting set.