Honda CRF 450 Valve Clearances?
The time has come to re shim my 06 450, and I am having a small problem (I think anyway). The exhaust valves have decreased to below the required spec and need to be replaced with thinner shims (as is usually the case), but the left intake valve has for some reason increased its valve clearance (from 0.16mm to 0.23mm). Is it normal for the valve clearance to increase? I thought they would only decrease... Any ideas? Unless the valve is being held open by something. Many thanks, Jim
Comments
The valve seats in the head take a constant pounding when the valves close - causing the valves to move up into the head and tighten the valve clearance.
Carbon build up on the valve seats and valves will hold the valves open a fraction (unnoticeable in the engine's performance) - which will loosen the clearance.
not really normal as i ahve a honda 450 r quad and the valves need ajusted all the time but possibly something was in your fuel such as sand ar dust or any thing that shouldnt be running in your gas
You want to do a clearance do you? Blow up the car.