YZ 125 Powervalve Q..

[Kidafa]

Hi All,

Just after a quick hand with a question in regard to the power valve on my 2001 YZ125. I have had the cylinder resleeved and am not 100% sure if the powervalves are closing properly as the back of them might just be hitting the sleve. Here are some pics: Do you think their ok?






Cheers in advance,

Chris

[mephistopheles]

it looks like the ring is hitting the power valve.


on the power valve there is a pin that is pressed into the shaft that the spring rides on. Over time the spring wears a groove in it and this allows the power valve to get closer to the piston. take out the power valves and inspect the pin. if it is grooved, you probably don't need a new one yet, press it out and flip it so the grooved part is pressed into the power valve and it will perform like new for the next few years.

Good luck

[racerfty]

i cant tell in the pictures, but if you got a strait edge and laid it on the sleeve on top of you power valve, is the valve tuching the strait edge, or how close is it?

[MXtras]

I am willing to bet the damage came from whatever caused the need for the cylinder to be re-sleeved. I might be wrong, but I don't think this cylinder has been run yet - there are no witness marks at all on the cross hatch.

You need to clean that valve up by removing/smoothing the wiped aluminum.

Scott