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Something that may need to be done often, adjusting the valves.

[edit] New information at the bottom of the page.

Not a real hard task, but like many it started with making some tools. We found that the gauges you can buy in most auto stores didn't work very well. They were too wide and needed a bend near the end. So I made some out of brass shim stock. I also made a wrench to hold the top of the valve adjuster because it is hard to grip the adjuster when you are trying to tighten the lock nut.


valve tools


You'll need to pull off the caps on the front and back of the motor. Working with the exhaust valve is a bit challenging because there isn't a lot of room around the front engine mount.


intake cover


exhaust cover


After removing the cover, you will see the adjuster.




Break the lock nut free, use the adjuster to get close to the value you need to set with the gauges.




And tighten the lock nut while holding the adjuster in place so it can't turn.


lock nut


Getting down to the exhaust valve is kind of a pain, here's what you see from the top. You'll need to go in around the front down tube and do your best.


front valve


Then just put the caps back in place and you are done for a few hours of operation.


[edit] We have found that the thread pitch on the adjusters is 0.5mm per revolution. What this means is that getting to the 0.12mm or 0.10mm specification can be done much easier. Turn the adjuster until it contacts the valve (lightly contacts), then back it out 1/4 turn and tighten the lock nut really tight. See the valve problem article here for the reason why it needs to be tight, and why you need Loctite in an area that normally shouldn't need it. Valve problem

What you get is 1/4 turn is equal to 0.125mm, so just a small amount less than quarter turn would be the 0.10mm needed for the other valve. Essentially both can run at 0.005 inch which is really very close to 0.12mm or quarter turn. Just makes life easier than having to fight with feller gauges in confined spaces with two other tools in the same space. You can check with 0.004 inch and 0.006 inch gauges in a go/no-go situation and call it good.