Another previous bike build, YB100 Yamaha.

[th62]

Not sure what year I built this bike, probably around the mid 80s. I think. It was probably around an early 1970s model.

The original bike was in pretty bad shape when I bought, not going and missing a few bits, so I bought another for parts from a bike wrecker, that gave me enough parts to put together one bike.

I started with the frame, removing about 150mm from the tail and welding a flat plate over the hole,it left to mount a tail light. I built a single humped seat and sewed up a cover for it on my Singer treadle. I fashioned a flat side cover from an old washing machine, bashed the edges over to form a rolled edge and attached it to the frame by two screws.

Using the washing machine again, I welded up an oil, tank and mounted that on the side with a polished aluminium cradle. The guards were shortened, springs, front and rear, exposed and painted, drop bars were welded up from a lawn mower handle.

Wheels were taken apart, hubs polished, rims derusted and polished, spokes painted and laced back together.

Engine was rebored and new piston, rings and gudgeons fitted. Head was shaved, and an expansion chamber welded up, from, you guessed it, the old washing machine. The huge barrel air cleaner sitting on top of the engine was binned and I beat up an aluminium one to sit directly on top of the right side engine cover inlet spigot. The YB 100 had a rotary plate induction system, meaning the carb breathed directly into the crankcase via a rotating disk, all hidden behind the right side engine cover. I modified the disk a little to change the induction timing and improve performance.

Engine cases, barrel and head painted black and side covers polished. The frame, guards and forks were also painted black.

The YB had surprisingly good performance for a 100cc bike, but with the mods it proved even quicker. The pressed steel frame was ideal for the small bike delivering surprisingly good handling due to stiff construction.

I rode it to and from work for a few years, before dismantling it and disposing of the parts at the local rubbish dump. All up I think it cost about $100 to build. It certainly got a lot of looks.