Not Pocket Sized Power
Sprockets and Steering Design
I used a Fairbanks-Morse centrifugal clutch with an inside diameter of 1/2". Thus, I had to use a 5/8". adapter to install the clutch on the engine. The drive is provided by a No. 35 link chain. The engine sprocket has 11 teeth geared to the large sprocket on the 36- tooth jackshaft. Turning on the other end of the jackshaft is a 10-tooth sprocket geared to the 60-tooth sprocket on the rear wheel. This setup makes up a 20-to-l gear ratio.
The baby-size wheels are four-inchers fitted with pneumatic tires and 1/2" bearings.
Frame members that hold the rear axle are bent into a U-shape, then brazed onto frame for added strength. (Right)
Happily, there is no hunting for materials. All parts for my bike were purchased locally from a lawnmower and mini bike shop.
(Left) The turning spindle assembly is a 5/8 x 4'/2-in. machine bolt through frame, on which two-piece handlebars turn. Unlike the off-road bike, this design is more permanent.