Douglas. (Stand 126.)
3½ h.p.; 68x68 mm. (494 c.c); flat twin four-stroke; overhead valves; mechanical lubrication; Degory carburetter; gear-driven magneto; three-speed countershaft gear; all-chain drive; Hutchinson 650x65 mm. tyres.
Douglas Motors, Ltd., Kingswood, Bristol.
The new Douglas sporting engine has already been described in our columns. Only in its main lines does it follow existing Douglas practice. The valve gear is quite new. Both cylinder heads are detachable, and above the valve rocker bearings (which form part of the casting), there is a small ribbed aluminium chamber, which is filled with oil about every thousand miles, and lubricates the valve rockers by a wick feed. Engine lubrication is also new; a worm-driven pump on the top of the crank case draws oil from the tank and forces it through a sight feed to two pipes which lead into the base of each cylinder. In addition to this, a hand pump is provided by which charges of fresh cool oil can be applied just above the moving cranks in case of necessity.
A new front brake is also fitted, which takes the form of a bevel edge disc of about 6in. diameter on the hub, with a parallel motion V grooved shoe embracing about one-third of its circumference. Altogether, it is a most interesting machine.
Another model, with the same innovations, has an engine of 350 c.c. capacity, the bore and stroke being the same as the standard 2¾ h.p. engine.
4 h.p.; 74.5x68 mm. (595 c.c): flat twin; side-by-side valves; chain and belt drive. Price £130; with sidecar- £170.
The 4 h.p. Douglas remains practically unaltered, for the experience gained during the war under extremely unfavourable conditions has made the machine entirely satisfactory in its present form. Details of the 2¾ h.p. Douglas are so well known that they need not be repeated here. Besides supplying the three-speed kick-starter model, which is priced at £105, the makers are listing an improved W.D. model with plain two-speed gear at £85.
The Motor Cycle, December 2nd, 1920. Page 717
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