1965 Royal Enfield GP5 250cc

1965 Royal Enfield GP5 250cc Racing Motorcycle

Having noted the success of the Greeves Silverstone, Royal Enfield decided that it should grab a share of the emerging ‘clubman’s racer’ market and began work on a 250 race-bike of its own.

Geoff Duke was hired as project consultant and Reynolds’ Ken Sprayson came up with a neat duplex loop frame, but the prototype was let down by the poor performance of its - at that time - under-developed Villiers Starmaker engine. Seeking a solution, Enfield turned to two-stroke guru Hermann Meier, who had prepared the Ariel Arrow ridden to a sensational 7th place in the 1960 Lightweight TT by Mike O’Rourke. Rather than being given the free hand he expected, Meier was told to keep costs down and use products from within the E H P Smith Group, Enfield’s owners.

1965 Royal Enfield GP5 250cc

Thus the GP5 had an Alpha crankcase assembly, Albion gearbox and a clutch based on that of Enfield’s roadster twins. Using a Meier-designed cylinder with four, rather than the conventional two, transfer ports, the GP5 engine produced respectable power – around 36bhp, which was more than the contemporary Silverstone – yet results on the race track were disappointing to say the least. Only on one occasion did the bike show its true potential, when Percy Tait finished 3rd behind the works Yamahas of Phil Read and Mike Duff in the 1965 Hutchinson 100 at Silverstone.

1965 Royal Enfield GP5 250cc

It was too little too late. By this time the writing was on the wall for the GP5 project; Royal Enfield was in financial difficulty and the racing department was closed to save money. The GP5 remains a fascinating ‘what might have been’ in the history of the British racing two-stroke. Engine numbers of known survivors suggest that around 30 were made.