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Discussion Starter · #1 ·
CB450K5 question, if anyone can assist. 15K mile engine that sat for 20 years before I acquired, I’ve put another 3k-ish on it since. Last week it started putting some oil out of the valve breather hose (enough to cause worry)and subsequently starting running poorly on one of the pots. Compression is good on both sides (~180psi at full rev), with little variance between the two, so the rings don’t seem to be the culprit. I’ve narrowed it to the valve oil seals, which I plan on getting into directly. Has anyone had this issue, and can these be replaced without pulling the cams? Any tips or tricks? Not had much luck with youtube, Haynes manual, etc. Thanks in advance!
 

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Valve guide seals would not cause a problem like you describe. What do you mean by "full rev" when doing a compression check? The engine should not be running.
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Ok, so I talked to someone smarter than I (not hard to find) who explained why the compression readings are pumped up artificially by a running engine. Back to the rings to do a true test. Apologies for the idiocy.
 

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As TOOLS said, test compression when not running, but it reads better when warm; make sure to lock the throttles open. Oil blowing out the breather is usually too much oil in the engine, or rings. Make sure the oil doesn't smell of gasoline - a leaking carb float will cause the over-filled oil condition.
 
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