Thread: Triumph Bonneville.

I've had an addiction to bikes ever since I got my licence in 1968, but can't stand stockers, so I usually modify them a little. I bought a Yamaha YB100 sometime in the 80s, it was a late 60s model from memory and a wreck. For parts I found another for a few $ and set about building a bike.

The YBs had a rotary valve, pressed steel frame, rudimentary electrical system and were typical of Japanese two strokes of the era, quite good performers. But of course I wanted more.

I started with the frame, removing about 150mm from the rear end and welding a flat plate in situ on which to mount a tail light.. The original side covers were plastic and badly cracked and weathered. The left side of the frame had a large hole giving access to the inside of the frame where the battery and rectifier were situated (pretty much the entire electrical system) and steel cover with rolled edges was made to cover the hole.

Rego was cheaper in QLD for solo sears, so I made a single seat with a bum stop and sewed up a vinyl cover for it on my Singer treadle. I made a tail light and mounted that on the flat plate directly behind the bum stop. Drop bars were welded up from 7/8" tube off an old lawnmower. The springs, front and rear were exposed and the guards shortened. Then I polished the hubs, removed the rust from the rims, cleaned up the spokes and laced the wheels together.

After pulling to motor apart, I modified the rotary valve, shaved the head, rebored the barrel, fitted new pistons and rings, painted the crankcase barrel and head black, put the motor back together and bolted it in the frame. The original air filter was a monstrous round drum sitting on top of the engine and connected to the right cover via a rubber hose, behind which the carb sat. That went in the bin and I beat up an aluminium filter housing which clamped over the spigot on the right side of the engine. I then welded up an expansion chamber with a removable baffle and fitted that.

Handlebar switch gear was polished and the bike rewired, not a difficult job for a YB. I managed to get a hold of some two pack paint in F111 green and painted the frame and guards with that. I didn't like it in green, so scrubbed it down and repainted it black. After the pictures were taken I welded up an oil tank from an old washing machine and fitted that to the right side with a polished aluminium cradle.

When I took it to the bike shop for a roadworthy, the guy said I couldn't register it as a solo because the holes in the swingarm for pillion pegs were threaded to take foot pegs. So, he pulled out his drill drilled through removing the thread and issued a roadworthy. Of course I couldn't insert pegs in the holes and secure them with nuts, could I. Strange rules!

All up, it cost me for a rebore and new piston, everything else was free, including the vinyl for the seat and paint which I got from different sections on the RAAF base. I rode this bike to and from work for a few years before dismantling it and dumping it at the local tip. The bike moved quite quickly, certainly a lot quicker than a stock YB and handled surprisingly well. I worked with a guy who had a later model H100 Honda, he couldn't keep up with it.

The bike got a lot of looks, Once I was stopped by a bike copper who just wanted to have a look at it.

I can't edit the title. So when I post about my Bonny, I'll title it Yamaha YB10.

Nice bike , looks like a cafe racer Deus style, interesting article on the LA times about making cafe racers , the 100's of hours that go into them. In inner Shitney the cafe racers are popular.
https://www.latimes.com/business/aut...124-story.html