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Tuesday, April 25, 2006

Motorbike stuff

Most of my recent posts are about work. I love what I do, and I'm up to my eyeballs in it right now, but that's just one facet of my life. I'm fond of motorbikes. If you look at one of the links to the right, there's one to the bike that I ride to work on a daily basis.

Now I'm posting a picture of the bike that I've had since I was in high school... my baby. I've had this since 1979, with a separation while I was on board the submarine. It's a 1976 Kawasaki KH500. Actually this one isn't mine - mine is covered in the garage. Unfortunately these aren't practical daily drivers. They're wheelie-prone (unintentionally) and have the most awful flexible frames in the world. The handlebars really get wobbly when you dive into a curve. For straight line acceleration though, they are super-fun! The original crotch-rocket!

Kawasaki built two-stroke street bikes for a number of years, culminating with the three-cylinder 500cc Mach III H1 and 750cc H2 models. The Mach III series ended with this model in 1976. The early bikes were pretty raw and uncivilized. By the time 1976 rolled around they had de-tuned the engine, and increased the angle of the front forks to minimize wheelies when the two stroke engine hit its power band.

I always felt this bike never delivered the performance it should. It always felt so muted when it hit the power band... so in 1991 I took it apart and made a few changes. I put in a set of older model pistons and cylinder heads, added expansion chambers on the exhaust, and increased the size of the main jets on the carburetors. There was a definite improvement! It still bogs down when you let out the clutch, and feels a little anemic below 3000 rpm. But about the time you get across the intersection, it's coming onto the pipe, carburetion and timing all at once. If you dare to leave the throttle wide open, it'll pick the front wheel off the ground. Not bad for an old heavy bike to power wheelie without "popping" the throttle or clutch!

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