Today in Motorcycle History

JD Motorcycles

JD motorcycles were built from 1922 to 1926 and marketed by Bowden Wire.
  • 1922 The first machine appeared as a motorised bicycles which had a 116cc two-stroke engine clipped to the inside of the front downtube of a safety-cycle frame. It had magneto ignition and drive by chain to a friction pulley working on the inside flange of the rear wheel rim. Clipped beneath the frame top-tube was a slim fuel-tank. It had braced, unsprung forks and appeared to be no more than a motorized bicycle.

    1923 A further model was added. This had an open ladies'-style frame.

    1924-1925 Those models continued with little change.

A report on the 1924 Motor Cycle Show reads, in part:

The J.D. motor cycle which is exhibited on this stand is particularly interesting, in that it is friction driven. An endless chain connects the engine flywheel sprocket to a larger one, adjustably mounted on a bracket brazed to the chain stay of the machine. This driven sprocket is built up with a friction roller and runs on a double row of roller bearings. Special frictional material conveys the drive to a U-shaped rim attached to the rear wheel.

The friction roller is attached to a swinging arm and so mounted on the chain stay that the whole can be swung into and out of action by means of a lever on the handle bar. When engaged, contact is maintained by means of the springs acting on an extension lever of the drive arm, but the ingenious feature of the transmission is that the swing arm carrying the friction roller is so mounted on the chain stay that the stronger the pull exerted on the driving chain by the engine, the greater is the pressure applied to the friction roller. Two machines running under electric power demonstrate this transmission.

The engine is a two-stroke, of 116 c.c.

Bowden Wire, Ltd., Victoria Road, Willesden Junction, London, N.W. 10.

Motor Sport Magazine

1926 Only the gents' model was listed, after which there is no further mention of the marque.

Sources: Graces Guide, Motor Sport Magazine

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