Photo ou archives : F-M. Dumas
5115
ROYAL ENFIELD
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.
SPECIFICATIONS
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.