how do you know when you need new valve guides

[bigdady536]

I am redoing the top end because my 2005 400ex was smoking white smoke like crazy and spitting out tiny bits of oil out the exhaust. I have the top end apart but the valves are still intact and was wondering when i remove the valve when a compressor how will i know if i should replace the valve guides. I would prefer not to because it cost about another 60 bucks just for the parts and the labor i don't have the tool to do it so i don't know how much someone might charge. but i figure if it's not necessary to replace then i wont do it but if anyone feels that it is a must then i guess i have just might have to. Please let me know how to tell if i will need to replace them. thanks Mike

[Ryanwolfe911]

Take the valves apart, and just stick the valve back in the guides, and see if you can wiggle it side to side. If it is excessive(it should be fairly obvious) Then they need replacement.

Good rule of thumb is to replace them on every second top end rebuild. Of course thatwill vary on your riding habits, etc.

You technically do need a special tool to drive them out, but I've improvised with punches and sockets before.