Offered from the National Motorcycle Museum Collection, c.1969 Royal Enfield 1,500cc Twin-engined Drag Bike

Registration no. not registered Frame no. none visible Engine no. YB15450 (front) Engine no. YA15037 (rear)

• Believed built by Jimmy Enz and ridden by Don Sliger
• Reputedly the first 'naked' motorcycle to exceed 200mph
• Restored condition

In the late 1960s Jimmy Enz of Lynwood, California built a twin-engined Royal Enfield drag bike with the aim of cracking the 200mph barrier for the first time on an un-streamlined motorcycle. The class record at that time was 191.302mph, set, of course, at the Bonneville Salt Flats in Utah, scene of countless world land speed record attempts. Jimmy was an Enfield enthusiast and had set a new class record of 135.314mph in 1964 on an extensively modified fuel-burning Interceptor, albeit one with but a solitary engine. He later ran the same bike at 153.58mph but destroyed the engine on the second run (two runs being required to set an average)

Twin-engined drag and sprint bikes were nothing new, even back in the 1960s, but rather than use the more favoured 650cc Triumph or Norton engines, Jimmy Enz chose to use two Royal Enfield Interceptor motors, which had the advantage of being 736cc in capacity. The two engines were connected by gears and housed in a sturdy-looking frame featuring a tubular spine with box-section tubes elsewhere; they were built to run on alcohol fuel with additional nitro-methane, which was delivered via a quartet of Amal Monobloc carburettors, suitably re-jetted. There were two separate aluminium fuel tanks: the left-hand one supplying the front engine, the right-hand one the rear. Ignition was provided by two magnetos. Given that a modern fully faired 1,000cc superbike requires around 200bhp to get within reach of 200mph, the power Enz extracted from the combined Enfield motors must have been well in excess of that figure. Even more surprising is the fact that he chose to retain the stock clutch and gearbox!

Jimmy Enz died in the late 1960s and the twin-engined Enfield passed to his friend, Don Sliger, who would have the satisfaction of proving that Jimmy's idea was no flight of fancy. In 1970 Don set a new class record at Bonneville with a two-way average of 194.724 mph. A mechanical problem intervened when Don went for the 200mph record but not before he had recorded a speed of 203.16mph, the first time an un-streamlined motorcycle had topped 200mph.

The machine offered here is the ex-Enz/Sliger record-breaker, which passed from Sliger to Les Powers of North Carolina and then to the National Motorcycle Museum in July 1997. The machine's mechanical condition is not known; accordingly, prospective purchasers must satisfy themselves with regard to its provenance, condition, completeness, correctness, or otherwise prior to bidding.