When to do Piston/Rings?

My 2001 has, I'd guess between 200 and 300 hours on the motor. I've adjusted the valves once, they were just slightly tight.

Recently I've been thinking I should probably change out piston/rings/gaskets. But the bike doesn't burn oil, and I still need the compression release to start it. But sometimes I think its down on power compared to when it was new.

What have others done? Wait for smoke, or do a leak-down test?

About the only thing I've noticed is that with the motor off, if I rest my foot on the kickstarter, it seems to fall through quicker than before.

Thanks for any help..

My 2001 has, I'd guess between 200 and 300 hours on the motor. I've adjusted the valves once, they were just slightly tight.

Recently I've been thinking I should probably change out piston/rings/gaskets. But the bike doesn't burn oil, and I still need the compression release to start it. But sometimes I think its down on power compared to when it was new.

What have others done? Wait for smoke, or do a leak-down test?

About the only thing I've noticed is that with the motor off, if I rest my foot on the kickstarter, it seems to fall through quicker than before.

Thanks for any help..

I recently replaced the valves on my 2000 WR400, it had the same problem with the lack of power, and i noticed a lot of carbon on top of the piston and inside the head. After cleaning it up, and installing a new cam chain, it is strong again. The piston and rings looked good. I would say it has around 250 hrs on it. Carbon on and around the valves may not allow them to seat all the way, causing less compression. Just my .02 worth..........check the chain also, mine had stretched about 1/2 inch (over 7 years) causing the timing to be off some.

Ok, so how did you clean it all up, and did you use OEM valves? Did you just replace valves, not guides and all that goes with them?

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