Page:Popular Science Monthly Volume 90.djvu/617

 �FOR PRACTICAL WORKERS

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��Dynamo Lighting System for a Motorcycle

Winner of Third Prize in Contest

THE modern automobile with its self- contained electric plant is much envied by the motorcyclist, but electric lights are equally possible for the motorcycle, with the dynamo in the illustration. Take a rim of an old bicycle wheel and bolt it on the rim of the motor- cycle to make a belt drive for the dynamo, which is fastened on the luggage-carrier supports. The dy- namo used on the motorcycle illustrat- ed was a discarded one taken from the ignition system of an automobile. The headlight used car- ried an 8-volt, 12 candlepower bulb. In running from 4 to 40 miles per hour a good light is pro- duced. When not running, a switch is used to turn the cur- rent on from the battery. The battery consists of 4 cells of dry battery placed in a box that is bolted on the braces of the lug- gage carrier. — David W. Freve.

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� ��The dynamo mounted on the luggage-carrier supF>orts is driven by a belt from the rear wheel

��Things to Know About Your Motorcycle Clutches

THE clutch, the intermediary between engine and rear wheel, has been to many motorcyclists more or less of a myster>'. Indeed, some of the early

clutches were weird and wonderful. How- ever, modern motorcycles are equipped with clutches which if properly used and

��cared for will give excellent service. In principle, a clutch consists of a number of disks contained in a circular casing. Every alternate disk is secured by projec- tions around the periphery which fits in grooves in the casing. On the outside of this casing is mounted a sprocket connected with the motor sprocket by means of the short drive chain. The counter- shaft, by means of which power is trans- mitted to the rear wheel, extends with- in the clutch casing and carries the other alternate disks by means of projections on the central hole of these disks. Strong springs are used to clamp the disks integrally to- gether when driving, and a screw-opera ti- ed thrust bearing is used to compress the springs and free the diskswhen theclutch is thrown out. Two general types of clutches are in use — the dry plate employ- ing steel surfaces in contact with raybestos linings, and the grease or oil lubricated steel on steel clutch.

With proper usage, the dr>' clutch should not require new raybestos linings oftener than once a season. When polished and dry, the linings may be improved by the application of glycerine. As the linings wear down, the copper rivets should be insp)ected carefully to see that they do not project above the surface of the linings. If the rivets do project too far, they will come in contact with the steel plates and cause the clutch to become harsh and jerky. The

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