BSA had aspirations of their own to build a vertical twin, in light of the success of Triumph’s Speed Twin, as far back as the late 1930s. War hostilities impeded the release of the 500cc A7 until 1946, but the configuration’s success was cast when an A7 reached 123mph at Bonneville in 1951.
Variations came thick and fast with Spitfire, Hornet, Lightning, Firebird, and Thunderbolt. The Thunderbolt was a simple, single-carb iteration, and slightly lower compression for increased reliability. Still armed with the effective A65 frame, brakes and cycle parts, the Thunderbolt was capable of 100mph performance.
The Thunderbolt on offer, hails from a Southern California collector of British and German machines. An older restoration that has held up well over the years with meticulous care, storage and regular, limited use. The bike has been maintained by local marque experts, Glory Motorworks, through the half a dozen years of ownership. As such, it starts easily and rides well. Brakes work well and all electrical systems work as they should. All-in-all, a good solid, nice riding icon of British motorcycling.