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Page:Popular Science Monthly Volume 89.djvu/943

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Popular Science Monthly

��929

��front wheel of the machine and all the movable parts of the spring-fork, leaving only the main fork as shown in Fig. 2. Bore a cross hole through the block G just back of the kingbolt and secure the fork to the block by means of the front axle. To maintain the motorc\'cle in a vertical position make the suppor: as follows:

���Rear runner and front-bob detail showing the plan of teetering and tilting devices

Make two eyebolts, A, Fig. 4. These bolts should be at least 6 in. long as they are used for adjusting the stay-rods B. These stay-rods arc made with an eye at the lower end for linking into the eyebolts A. Bend the upper ends into a hook to engage the fork stem. Place these in position as shown and tighten the nuts at the lower end of the bolts A, so that the motorcycle may be readily adjusted and secured in a perfectly vertical position. Do not use continuous rods for this purpose, as there must be a hinge-action at the eyebolt to allow for the \ertical movement of the rear wheel of the motorc>'cle.

Tlie rear of the motorcycle is supported by the brace L, Figs, i and 2, which is shown in detail in Fig. 5. Make two guides A, and secure them to the frame sides by means of screws or bolts to allow an opening between the guides just wide enough to bear against the luggage-carrier. The crossbars, A'l, Figs, i and 2, should be located at least 4 to 6 in. above the top of the luggage-carrier. Cut a crossbar B, Fig. 5, from a piece of hardwood ^4 in- thick and notch it at the ends as shown in the detail C, making them wide enough to let this bar move freely on the guides A. Between B, Fig. 5 and the crossbars .1/, Fig. I, insert two spiral springs each strong enough to exert an initial pressure of at least 25 lbs. and preferabh- 50 lbs. when in jjosition. The purpose of these is to prevent the motorcycle from jumping up and down when running over obstructions.

To transmit the driving force from the motorcycle wheel to the bob take two pieces of J/2-i'i- gas-pipe, or i-in. No. 16-

��gage steel tubing, flatten them at the ends and drill one end to fit over the rear axle ends. Let these tubes extend forward as shown at P, Fig. i , bolting the forward ends to the frame sides close to the front ends. It will be readily seen that without these braces the dri\e would be transmitted to the sled through the front forks which should not be subjected to such strain.

Sleermg Apparatus

Steering is accomplished by means of a wheel. The steering post may be con- structed of I -in. gas-pipe and the wheel may be simple or elaborate, according to individual taste. At the lower end of the pipe secure a spool of hardwood about 3 in. in diameter with about i in. of the pipe pro- jecting be}ond the spool. On the crossbar N, Figs. I and 2, place a piece of flat iron about 34 in. thick as indicated, thus fur- nishing the support for the lower end of the steering post. Run a pin through the end of the pipe or screw on an ordinary pipe-cap to prevent the post from backing out of the collar-plate. Support the upper end of the steering post by passing the post through the upright guideway at the rear of the motorcycle. The detail is shown in Fig. 6.

A piece of J<4-in. cable wire is anchored solidly to the spool and two turns of it are run around the spool each way from the anchor and wrapped so that the wire will leave the spool in each direction from the bottom. Pass these wires around grooved pulleys pivoted on the ends of the crossbar N, Fig. I , and thence to the crossbar of the

���Guide for the rear part of the motorcycle and steering cable supporting connections

front runners. It is readily seen that by turning the steering wheel to the right the right end of the runner will be pulled back- ward and the motor-tiob will steer to the right, and vice versa.

The Controls

The question of control is a matter to be determined by the kind of motorcycle used, and only general suggestions will be offered. The spark and throttle can be

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