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My 04 200 has approximately 100 hours on a fresh replate and Pro-x piston. Most of my riding is low RPM technical trail, with logging roads between to clear it out. It runs great, no power loss, just wondering how long do most run a piston and rings?

In my racing past it was always changed every 5 races or 15 hours whichever came first. I think Pro-X recommends like 25 hours. Nowadays I run it until I see a noticeable decrease in compression. I check compression every few rides and keep notes. My current piston/rings have about 75 hours on them and have no noticeable loss in compression.

I run only forged pistons in the 220 and I go until I start getting towards the lower end of compression spec. I think I'm over 400 hours on my current Wiseco and she is about due. Oh, and I don't ride my bike easy! If I was running a cast, which you should never use in a 220, I would go no more than 100 hours or so.

If I had a fresh replate, I sure as hell would not let it run real long.Even at 1,000 RPM, the piston is riding against the thin film of oil between it and the cylinder... 16.6 times per second! Rip it to 10k RPM for 166 per second.

KDXGarage wrote: ↑10:16 pm Aug 04 2022 If I had a fresh replate, I sure as hell would not let it run real long.Even at 1,000 RPM, the piston is riding against the thin film of oil between it and the cylinder... 16.6 times per second! Rip it to 10k RPM for 166 per second.

I know not an apples to apples comparison but here in Thailand there are many many 2 stroke scooters with 70,000klms and never had a rebuild, seems a bit extreme to be changing pistons often

Maybe I take a slightly different approach. I'll change rings on an existing piston that is still good. It's the rings that ride on the cylinder walls so I always want to make sure i have good solid ones in the bike. A broken ring is a big time problem. Generally I would put in new rings about every 3-5 races, maybe more often if doing a lot of hard riding between races. I also watch compression; not so much the specific number but how much it changes over time. I always kept a notebook that gave me a running history of compression so I could see a trend. As long as we're talking, fresh oil every race, plug every other. Fresh premix using 93 octane alcohol-free pump gas.

Compression is 135 psi, the usable range stated in the manual is 95 -151psi . This is the first check on this top end so I don't have a reference but will keep track from here on.

Forgot,, Compression corrected for altitude is 122 psi @ 3500' elev. so right in the middle of the service range.