Here's a simple fix for worn kick starter shaft boss in a clutch cover. This is off my 1981 YZ465 Widomaker. These have so much compression that they wear out the hole in the clutch cover and can also break part of the steel kick starter shaft, both of which happened to mine, so luckily my 1980 YZ465 came with a spare engine that had a good shaft but a bad cover, soooo, I had the kick starter shaft hole in the cover bored out then had a bronze bushing made as thin as was reasonable so as to maintain as much strength in the cover as possible. I had it made with only around .001" interference (press) fit te reduce the chance of the cover cracking, then had the id machined .00075 larger than the shaft, and whala, even better than new because the bronze will wear far more slowly then the mag case will.
Since it would still be hard to kick start this harbinger of doom, and the stock compression can still break the kick starter shaft, I had the head machined for an "automatic" compression release. This is the same style that is used on some chain saws and other small engine power tools, and you simply push the button and it locks into place to open the valve, then when the engine starts, the compression is then high enough to automatically close the valve. Unfortunately, the decompression valves for the chain saws etc seem to be poor quality, and I read about some failing and dropping the valve into the engine and f'ng it up, so I did a Google search and found one company that made them in the US out of all stainless on a CNC machine, and they were selling them like hotcakes to people that have high perf Harleys, so I got one from them and it was only around $25.00.
I then had the head machined for it but had to remove some cooling fins to make room for it, so I made some some fins to add to part of the head to compensate a little for the fins I had to remove.
I hope to have this monster done by Tuesday, and may then take it out to the next vintage race next weekend at Perris and attempt to race it....providing my health insurance is still active and I don't wuss out.
C'mon barns...don't be a PUSSY!
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