Douglas 1920 4 HP 596 cc flat twin frame#13014 engine # 12041
This Bristol-based firm developed the horizontally opposed fore-aft unit in about 1907 and continued utilising this engine layout well into the thirties.
The earliest Douglas models had direct belt drive, but in 1910 a two-speed gearbox was added, with the control on top of the petrol tank. Douglas machines became very popular because of their lightness, ease of starting and speed: in the 1912 Junior TT races Douglas took first, second and fourth places.
In the First World War thousands of 2 ¾ HP machines were commissioned for use by despatch riders and performed splendidly.
In 1915 a 596 cc model was introduced to cater for the need for a more powerful sidecar puller.
A notable difference in engine design with the 2 ¾ HP model is the wet sump oiling system.
A year later the 4 HP model was improved in a number of ways.
To mention a few: other front forks, new design of exhaust, frame and tank alterations, front and rear brake changes, many small engine design improvements.
To sum it up: quite another machine! Between 1916 and 1921 not many changes were made; a notable change for 1920 was the introduction of a dry multi-plate clutch on the gearbox.
The 4HP disappeared from the range in 1924.
This machine is unrestored and with it comes a not-quite-complete sidecar ( with newly made body) and ditto spare engine.
Accessories are a pillion seat and a bulb horn.