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valve guide seals

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thank you...the "lap valves to seats" whats that? is that where ou get that abbrasive stuff and spin the valve to make a better seat??

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I was told not to lap valves anymore as all newer bikes (relative term, I was told anything from around 1990 on up) have a coating on the valves for hardness and lapping the valves will remove the coating and significantly impact the life of the valve. Has anyone else heard this?? I also read an article that showed an animated cutaway of a lapped valve depicting an off angle cut seat because of the polishing compound creating an lift between the valve and valve seat while lapping. The article said it is always best to use new valves and re-cut the seats for the ultimate fit. Can anyone here tell me if they have heard the same thing or have any suggestions. Thanks.

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i actually read something like that in the manual last nite...and i was starting to question it...

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I was told not to lap valves anymore as all newer bikes (relative term, I was told anything from around 1990 on up) have a coating on the valves for hardness and lapping the valves will remove the coating and significantly impact the life of the valve.

I have heard that too. But if you're cheap or poor, or both like me, lapping the valves is still a good alternative. I recently did mine and the results were noticable. Of course I think it may have been done to my bike before as I bought it used and the coating seemed to be missing from the sealing surface of the valve already. If you can afford new valves and a valve job that is the way to go. If you're on a budget lapping is a good alternative. $600+ vs $100-.

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well when i got the bike the ONLY thing wrong was those seals..they went bad and started leaking oil...i baught a few new things and honed the cylinderbut hopefully itll work fine without lapping

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you can pull the head and compress the valve springs and replace the seals only, do a leakdown test prior to dissassembly, if they ain't leakin don't bother tweakin (lapping).

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If someone (me) replaced the valve seals without lapping the valves, would the valves eventually wear back in and achieve good compresion? Fortunately I did the seals on my 500 one at a time so the same valve went back into the same guide and the bike runs great. Might have to do the same thing to my 250 though...

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WOOT im so proud..i changed all 4 valve seals in 20 minutes myself..and with the helo of my clymers manual...and with some help from you guys..THANKS

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