Royal Enfield - 3 HP Prototype
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Royal Enfield D2-492-51-15
Photo ou archives : F-M. Dumas

Capacity : 425
Model : 3 HP Prototype
Production : 1913 -
Category : (R) Street Bike


3 HP Twin - 1913

"Built like a gun"

Royal Enfield originated in the pedal cycle boom of the 1880s and built its first powered two-wheelers in 1899. After a few false starts, the company returned to motorcycle production in 1910, with a Motosacoche-powered lightweight 2.5 hp V-twin.

Cushioned Drive

A major technical innovation of 1912 was the Enfield patent "Cush-Drive," in which transmission irregularities were ironed out by rubber blocks incorporated in the rear hub. It remained a feature of Royal Enfields, right up to the end of production in 1967.

Triumph and Tragedy

Making its first appearance on the Model 180 of 1912, a 770cc JAP-engined sidecar mount really established the Royal Enfield name. In 1913, the company – whose slogan was "built like a gun" – introduced its own power unit, a 425cc V-twin, designed by W.H. Guillon. The prototype differed in several details from the production model. It was started by a handle beneath the saddle linked to the engine by chain-and-sprocket gearing. A major innovation on the production models – which had F-head engines – was full dry-sump pressure lubrication. A 350cc version derived from the 425cc model raced at Brooklands and in the 1914 Junior TT. After a tremendous battle with the Douglases, F.J. Walker finished third with a 44 mph average. Tragically, dazed by a fall on the last lap, Walker failed to stop after crossing the finishing line and fatally crashed into a barrier.


Engine: 425cc air-cooled V-twin four-stroke; magneto ignition; total-loss lubrication

Power Rating: 3 hp

Valves: overhead

Fuel System: carburetor

Transmission: 2-speed, chain final drive

Suspension: Druid girder forks (front); rigid (rear)

Brakes: rim (front); dummy belt rim (rear)

Wheels: 2.25x26 inch wire clincher (front & rear)

Weight: 165 lb

Maximum Speed: 50 mph

Believed to be the prototype of the 3 hp V-twin, this 1913 Royal Enfield has its chain-driven magneto between the cylinders; production models carried it ahead of the down tube.

Motorcycle encyclopedia Moto Passion, realised by François-Marie Dumas, include almost 2000 photos presented with an exhaustive history of the motorcycles exhibited.

This unique collection has been realised with the participation of many specialists. With many thanks in particular to Yves Campion, Michael Dregni, Didier Ganneau, Jean Goyard, Helmut Krackowizer, Michel Montange, Christian Rey, Bernard Salvat, Mick Woollett, etc

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