P&M Motorcycles

P & M 1914 750cc 90° V-Twin

A NEW 750 c.c. TWIN P. & M.

Entirely New Design, embodying a 90° Engine of 6h.p., Four-speed Gear, and Automatic Carburetter.

RUMOURS of a twin P. and M. have been prevalent for some time, and it was recently our good fortune to have an opportunity of inspecting one of these interesting machines at the premises of Messrs. Phelon and Moore, Ltd., 4, Percy Street, Tottenham Court Road, W.C. It will be seen from the accompanying photograph that tile 90° twin engine is very neatly stowed away in the Frame. The front cylinder assumes the position taken by the cylinder in the case of the single, while the rear one is similar but not quite the same as the other, and is not interchangeable with it.

Two interesting features of the engine are the method of driving the magneto and the exhaust valve lifter. The former is brought about by a bevel formed on the back of one of the two to one gear wheels which transmits the power through a shaft to skew gearing on the magneto. The drive is silent and effective, and is easily accessible, as will be seen from the accompanying photograph. which shows the case with hinged lid for protecting the mechanism. With regard to the exhaust valve lifter, on the end of the shaft is a toothed wheel meshing with teeth cut on part of the periphery of two cam wheels. When the lever is pulled over, the cams are raised and come into action with the valve raising levers. It is interesting to note that all the tappets are fitted with rollers.

The bore of the engine is 76 mm., and the stroke is 82 mm., giving a c.c. of 750, and the engine is called 6 h.p.

Oil is delivered to the front cylinder, and the space between the baffle plates in the back is larger than that in the front, the back cylinder gets plenty of oil. The tank holds two gallons, is well designed, and looks by no means too large for the machine. The ordinary form of P. and M. two-speed gear is fitted, but a four-speed gear is in preparation, which consists of an ordinary P. and M. two-speed gear and a two-speed dog clutch gear box fixed to the bottom bracket - an ingenious and simple arrangement which should work admirably.

The engine is arranged in the same way as a single, so that it can be swung forward and the cylinders removed.

Messrs. Phelon and Moore have been studying the question of a twin for a good many years, .and they have now succeeded in bringing out a handsome and thoroughly practical article. It has not, however, quite reached its final stages, though only a few detail improvements have to be added. The carburetter is the Claudel-Hobson, which gives an ample amount of flexibility to the smooth running engine, but we understand that a different type will be fitted as a standard. Other P. and .M. features, such as the front fork, chain cases, kick starter, brakes, etc., have been retained practically without alteration.

The Motor Cycle, July 23rd, 1914. p123.

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