The Harwood Cycle Attachment.

We may say that the neat attachment, weighing under 21 lb., which is marketed by the Harwood Motor Co., Long Lane, Bexley Heath, Kent, gives considerable promise both from our experience when riding the machine, and from the general arrangement of the power unit.

A two-stroke engine having a bore and stroke of 52 x 52 mm. (110 c.c.) is held by two clamps fixed round the two down tubes of the cycle frame. The magneto is mounted on a platform, which in future models will be cast integrally with the crank case, the rear end of which is clamped to the saddle down tube. The usual two-stroke practice has been observed in the construction of the engine, whilst a useful fitting, an inspection plate, is secured by two screws to the transfer port.

As might be expected from an attachment of this type, the final drive, which is by roller chain to an auxiliary sprocket on the rear wheel, is liable to considerable chain snatch, and in order to obviate this a neat cushion drive is incorporated in the transmission system.

As may be seen from the diagram, a gear-reducing pinion is in direct engagement with the crankshaft pinion. The drive, however, is taken through an arm which is in contact with the pinion through four coil springs, which tend to absorb the snatch in the chain. The arm thence conducts the drive, through a spindle running in a phosphor bronze bush, to the chain sprocket.

The magneto is gear driven through an intermediate pinion in engagement with the driving pinion.

An Amac carburetter is used, and is supplied from a circular tank, which is capable of containing half a gallon of petrol and oil mixed - a quantity sufficient, it is claimed by the manufacturers, to carry the machine for a distance of seventy-five miles.

The makers are prepared to offer the power unit alone or complete fitted to a pedal cycle. The price of the former is £20.

The Motor Cycle July 29th, 1920.