my 02 rm250

took my 02 rm250 to the local track again today, runing great all day. Untill

all of a sudden out of no where, it started knocking/ ticking. I shut her down

as fast as i could, what happend? Engine was rebuilt last summer and has

been a very good dependable bike. Last i checked it had 135psi comp. May b

a wrist pin came loose.

All though i was pissed off,because i cant ride it anymore this summer. I was

also happy it wasnt my 4 stroke. Witch would take a small loan to rebuild the

450 comparied to the 250 2t. I guess ill find out when i take her apart.:D

No way to tell for sure until you tear it apart but if it wasn't smoking it was probably in the top end. Gotta love the 2 stroke, jacked up top end (200 bucks).

so i took my top end apart today. It looks like the top piston ring hit the exhaust valve and pushed ring up into the piston. The cylinder looks good, and i think i will be able to get by with a fresh hone and fresh piston. My question is how does this happen? ring gap not set right? The thing is that i have a least 10-15 hours on it after the last time i had it rebuilt. Any help would be great. thanks

this may start a whole other discussion, but what is your mixing ratio and what oil are you using?

It's getting colder out, and bikes are running leaner. Your bike was probably running a little lean, and you didn't even know it. Running lean causes more heat, especially in the area of the exhaust. 10-15 hrs on that piston indicates everything else was fine. No big deal, poop happens!

or your left crank seal may be leaking

killerdwarf77 i think u are 100 % right, i never even gave it a thought untill know. It had to be running lean. Its jetted for summer not 50 to 60 degrees. I feal like a dumb ass, i should have rejeted it for the cooler temps i was riding in. Live in learn i guess! As long as i cylinder is ok, and it can be honed again ill be happy.

You probably have a powervalve issue.

like what ? Out of no where it closed to far or what? Even if it didnt work i shouldnt get in the way of the piston. The bike ran great all day, i went around a corner and let off the throttle to slow down for the next one, and it started knocking.

Sometimes the parts where enough for the main valve to go a little too far into the cylinder and catch your rings.

ya that might be what happend, so what do i need to do? make sure valve is set the correct way? I do know that i was running to lean for sure, i never rejeted for the cooler temps. plug shows running lean also.

Well, it's been almost 2 weeks. Did you figure out what it was?

Well, it's been almost 2 weeks. Did you figure out what it was?

? did u read ? ring hit the exhaust valve, i just took her apart today. Just dont know if it was the valve that caused it or from running to lean.

My service manual says something about checking valve to cylinder clearance. I'll look into it and tell you what it should be, but I have a 1998.

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