1957 Triumph 200 Twin Prototype
Engine: 200cc air-cooled 2-stroke parallel twin, 51mm x 49mm bore and stroke, 20hp @ 8,500rpm
Carburetion: Single 24mm Mikuni (Amal originally)
Transmission: 4-speed, chain final drive
Electrics: 12v, coil and breaker points ignition
Frame/wheelbase: Tubular steel single loop/51in (1,295mm)
Suspension: 30mm telescopic fork front, dual shocks rear
Brakes: 6in (152mm) SLS drum front, 7in (178mm) SLS drum rear
Tires: 3.25 x 17in front and rear
Weight (dry): 210lb (95kg)
In 1957, Triumph’s chief engineer and later CEO Edward Turner ordered his R&D team at Triumph’s Meriden factory to chuck a prototype engine they’d been working on into the bin.
Fortunately, the development guys didn’t scrap it, and the result is today on display at the Sammy Miller Museum for all to see and hear in action, having been restored to running order 20 years ago, after Miller acquired it in 1995 as just a prototype engine — one unlike any other in Triumph’s postwar lineup — and frame.
So what was it? In 1956, the year after Yamaha’s motorcycle division was founded and by which Suzuki had been making small single-cylinder bikes for just three short years, Turner decided to have his Triumph design team build an experimental 200cc 2-cylinder 2-stroke engine of the exact same type that would propel the products of Japan Inc. to worldwide supremacy in the coming years. Well, except for Honda.
Turner was interested in using the engine in the Triumph Tigress scooter, due to be launched in 1958 as the BSA Group’s entry into the then-booming scooter market dominated by the Italian Vespa and Lambretta 2-stroke singles. In the end, the Tigress and its badge-engineered BSA Sunbeam sister were powered by either a 10-horsepower 249cc 4-stroke 2-cylinder engine or a 7.5-horsepower 173cc 2-stroke single, both of them air-cooled. The 2-stroke was a development of the BSA Bantam engine, but the 4-stroke was a completely new parallel-twin with gear rather than chain drive to the gearbox.
Order the January/February 2018 issue of Motorcycle Classics to read more about the 1957 Triumph 200 Twin Prototype. Contact Customer Service at (800) 880-7567 or contact us by email”