VALVE CLEARENCE - WHEN TO CHECK?

HOW CAN I KNOW THAT I HAVE TO CHECK AND ADJUST THE VALVE CLEARENCE ? I HAVE A 2000 YZ426 AND I NEVER DID IT BEFORE....

I RIDE ONCE A WEEK OR TWO WEEKS ONLY SO THE BIKE DID ABOUT 3000-4000 KM ONLY ....

check soon... it is easier than you think. the manual is great :) I am finishing mine this weekend.. IF my pads are in.

Also.. I was wondering how easily the cam chain could skip gears on the crank when I pull the cylinder head off.

I want to see my valves! and piston!

[ February 05, 2002: Message edited by: crazyadam ]

It should be about that time, considering the time you have on yours. Things to look for is fouling plugs, becoming harder to crank, backfiring,if they are getting tight, which, the 426s tend to do. If they loosen out of spec you will hear them rattle. :):D

I have a 2000 with about 15 hours or so on it. I just pulled the cover.

My intake valves (3) are between the low end and the nominal spec - each seems to be just a tiny bit different.

My exhausts (2) are on the low end of the spec - boarder line as far as needing to do anything with them.

As long as they are in spec - I'd like to just leave them alone - does anyone see any danger with letting them run until they are are just under spec?

Thanks for any advise.

Boomer

When you take the cylinder head off, I don't think the cam chain can skip a tooth, at least mine didn't. It can only skip if you take the forward cam chain guide out, otherwise the front and back guides hold pressure against it so it can't skip. This happened to me, but only because I had my cylinder off and didn't get the forward guide all the way down in it's slot. It's a good idea to tie your cam chain up with a zip tie or string just so it doesn't fall down. And now that I think about it, I don't think you can even get the guide out without taking the cylinder off, maybe some of the guru's can correct me?

I just checked mine last week and they were all in spec. although closer to the tight side, I don't see how they could get any tighter with wear. Can they? I figured that if anything they would loosen up as the motor wears. Anybody have any other ideas?

just read another post and answered my question about valves getting tighter, shows what I know. guess i'll keep a close eye on them and see if they actually tighten up out of spec.

they will tighten up with time. the valves are harder than the seat they butt to. so the seat tends to wear and makes them tight, more so on the 01 and 02. i made mine a hair loose so they could seat in.

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