Page:Motors and motor-driving (1902).djvu/189

Rh Moisture is a frequent cause of trouble on motor-cycles. Rain or damp may lodge on the porcelain of the sparkingplug or between the terminals on the ebonite plate on the commutator, or between the terminals of the coil. Remedy. Carefully wipe the affected parts with a dry rag and cover them with a little oil or vaseline.

Battery Short-circuited.—Spanners, oil-cans, tire-pumps, &c., have been known to jump on the top of batteries, thereby connecting the terminals together and causing a 'short-circuit.' Remedy. Always carry the battery in a separate box, away from other things.

Burnt Contacts.—The contacts may become burnt. They should be cleaned up with a smooth file. Loose Contacts. The platinum points on the trembler can become loose. They should be knocked up with a light hammer.

Oil on Contacts.—It frequently happens that oil and dirt accumulate on the platinum contacts, which interrupt the free flow of the current. Care should be taken, therefore, that they are perfectly clean.

Retard Sparking for Starting Engine.—When starting a motor the spark should always be placed as late as possible.

.—This system is practically identical with that used by Messrs Panhard-Levassor, Daimler Co., Napier & Son, &c. While the general lines of the De Dion have been followed, one important variation is introduced viz. the alteration in the position of the trembler. In engines running at a lower speed than 1,000 revolutions per minute the De Dion is not found to answer satisfactorily, and a different method of causing a vibratory contact had therefore to be devised. On the Benz system the notched cam is replaced by a round fibre disc, a brass strip being attached to it over oneeighth its circumference. This strip is connected with the iron axle on which the sleeve revolves. A spring to which is attached a knob,, rests upon the disc. A wire connects it with the battery. It will be seen then that as the disc revolves