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Valve clearness

elipeer

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Hi there,

I checked today the valve clearness on my CB750F 1980, all 15 valves where in the correct tolerance except the the 2 exhaust valves on cylinder 4 that are well to close, I couldn't even insert 0.002 inch feeler gouge, very tight, almost no clearness at all.

I got this bike from a guy that told me it was standing for years, so I basically replaced all rubbers, oils, electrics, put CR carbs and did not fire the engine yet.
I have a shim removal tool, should I change to a thinner shim?
Isn't it strange that all valves clearness are fine except 1?
Shouldn't clearness increase in use not become smaller?

Please help,
Thanks,
Eli.
 
Yes you need to adjust the clearance. If you leave them tight you will burn the exhaust valves. It depends on if the clearances have ever been checked before if this is normal or not. If this is one of the first valve adjusts then it is nothing to worry about. If this particular valve has needed adjusting previously then it indicates a valve and seat issue. It is normal for clearance to get tight on this valve and cam arrangement as the only thing that will wear is the valve and seat and when wear occurs the valve works its way farther into the head bringing the stem closer to the camshaft lessening clearance.
 
Thanks, I don't know history of the bike.
It has 30,000 miles on clock, got it after standing for years.
So a thiner shim?
 
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