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Valve adjustment question.


superhawk996

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I have the head off and would like to do the valve check before installing it so I can order all the parts I'll need at once. I assume I can turn the cams to where each set of followers are on the base circle of the cam and check there rather than installing the head and doing it by the book-?

Reason it's off is a pair of exhaust valves were leaking, #3 cyl. I assume they were too tight at some point and that screwed them, they didn't look too bad and weren't burnt so I coulda probably just lapped them but had them reground to be sure. #2 cylinder's intakes were at double clearance, the rest were in acceptable limits. This was Cecome's motor that I bought from him, it was said to be rough running, had a tick, and low compression; guessing the low compression was the rough and the loose intake valves were the tick and hoping nothing worse. This was after he'd taken it to at least two places to try to figure out and fix the issues, both did valve adjustments the second place caught the compression issue but didn't diagnose the cause. I don't recall their numbers but I got 190 on the good ones and I think it was 90 on the one with valve leaks. The cylinders look good, there's no wear ridge and the honing is pretty clean. All the internals I can see look nice & clean as well other than a fair amount of carbon that I'll be cleaning off.

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Most modern motorcycle engines utilize valves that have a very thin and hard coating.
Grinding the valves generally isn't recommended as the process removes this coating..
I think I'd buy 2 new valves if I were concerned about putting a lot of miles on the engine.

Having said that, you can set the valves the way you describe as long as only 1 cam is in the head at a time.
You may consider removing all the valves, decarbonizing them and the bowls, lapping them and reinstalling them with new seals.

There are factory, cheap aftermarket and expensive aftermarket seals available.

Hank

Edited by HANKSXXX
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Didn't know about this coating, damn. I thought about cleaning up the other valves & ports, which would then force me to do a little dremmeling, I'm surprised at how rough the ports are and the ridges near the seats. Curious; why only one cam at a time?

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Didn't know about this coating, damn. I thought about cleaning up the other valves & ports, which would then force me to do a little dremmeling, I'm surprised at how rough the ports are and the ridges near the seats. Curious; why only one cam at a time?

Valve interference...without the cams rotating as a pair in a timed condition, you run the risk of bending a valve.

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