valve clearence gone bigger?

1 reply to this topic
  • 04WR450man

Posted May 19, 2011 - 04:16 AM


Hi all, I
I checked the valve clearance on my 04 wr450 this morning, I had to re-shim all 5 valves because the gaps were one size too large. The bike has hotcams fitted, was shimmed when I fitted them a while back.
Is this normal? I thought they got tight with wear and use etc?

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  • Sknight

Posted May 19, 2011 - 05:57 AM


In typical use, yes the clearances tighten up. What happens is the valve and seat mating surfaces wear over time and for lack of a better term the valve rises up into the head tightening up the clearance.

In your case though what you're seeing is the cam lobe surface breaking in. It's hardened but it still initially wears a bit until it gets that pretty polished surface plus the metal compresses a bit under pressure.

I'll bet next time you check it it'll be just fine.

Edited by Sknight, May 19, 2011 - 07:30 AM.


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