Sunbeam Motorcycles

Today in Motorcycle History

Sunbeam 1915 796cc V-twin


6-7 h.p. Engine, Re-designed Gear Box and Clutch.

THE most novel machine of the Sunbeam 1915 range is the twin-cylinder 6-7 h.p. machine. An entirely new engine is fitted to this mount of a bore and stroke of 73x95 mm., giving a capacity of 796 c.c.

The valves are of the mechanically-operated side-by-side type, a new design silencer is used, but the most important change apart from the engine is the new gear box, which is much stronger than formerly, and the change of gear is effected by a pair of sliding clutches actuated by a rack and pinion and a cam action. The gear teeth are very wide and strong enough for almost any work. In addition to the gear, the clutch as well as the operating mechanism has been redesigned for next year. Last year the plates were carried on pins; they are now supported on keys, and there are seventeen plates in the new design, nearly double last year's total, thus giving increased frictional surface.

The mudguards have been greatly improved, and leg shields are also fitted in front of the footboards. The wheels are, of course, detachable and interchangeable as before.

The engine of the 3½ h.p. machine has also undergone various alterations, though the bore and stroke remain as before. The magneto is now driven by a silent chain. The improvements in connection with the gear and clutch also apply to this model. The 2¾ h.p. mount remains practically unaltered for 1915, so satisfactory has it proved.

The Motor Cycle, November 19th, 1914.