doh. 11 year old piston gives up the ghost.

[stainlesscycle]

zipping along on some single track today for about half an hour and bike just stopped. i thought it was a holed piston - i've had one hole before and it seemed just like it.. pulled plug and it sure looked like it. half white/half black plug.

but i finally got it home, tore it apart, etc...(after a quick 3 hr trip to smith's powersports to pickup a new piston - in stock! thanks!)

and this is what i found. looks lean, but also looks like something else happened - any guesses??

my cylinder is gouged too. guess i gotta send it out. anyone have a decent 200 cylinder laying around??

[stainlesscycle]

and the cylinder.

[Dude]

Wrist pin clips intact. I had one of those let go on a blaster once. Looked just like that.

[stainlesscycle]

wrist pin clips were both intact.

[Moto-x]

did a piece of the piston ring break off

[Rick]

Yes....looks lean?? wrist pin looks dry? what does the head look like? Sparkplug in tact? What about the reeds? Are you missing any screws from your crank stuffers? Something rattled around in there!

Good Luck!

Rick

[HenrikSchmidt]

It's the piston ring giving up. on pic.3 you can see the end of the ring bend up, and there is a big piece of the ring missing.
I've seen this a lot of times, when you don't change the rings for too long the metal get's tired and finally give up, you can run with the same piston for a very long time if you just change the rings in time.

[stainlesscycle]

yeah, it sure looks like ring died. i replaced rings last year.

[stainlesscycle]

Originally Posted by Rick

Yes....looks lean?? wrist pin looks dry? what does the head look like? Sparkplug in tact? What about the reeds? Are you missing any screws from your crank stuffers? Something rattled around in there!

Good Luck!

Rick

head looks surprisingly good. plug looked bad...

i think it was lean and the ring gave up. oh well. now i get to split 2 300 motors today, make one good one from the 2, pull the 200 motor, and jam the 300 motor in. then jet and tune. all by saturday night. fun.

[HenrikSchmidt]

Originally Posted by stainlesscycle

yeah, it sure looks like ring died. i replaced rings last year.

I'm new to gasgas, and I was wondering how often do you need to replace the piston And/or rings. On the mx bikes i owned before I changed rings for every 20-30 hours and the piston when it's out of spec. or looked bad.
Is it too often for the gasgas? when i bought my ec250 the counter said 48 hours, and i was thinking to do the top end soon, but the bike runs really good and don't seem to have lost comp. how often do you guy's do a top end?