2001 rm 259 died


I bought this rm250 in what seemed a good condition. I went for a ride today, and it seemed like a fouled a plug, so I replaced it, it wouldn't start. I pulled it out again and the plug was still dry. I'm in the process of checking the carny and jets. Any other idea what it could be? Fuel runs out the over flow in the carby as well.

Thanks for any and all suggestions

Edited by ejboaklyn_crf250r

Run a compression test, check for spark. Cover the basics and report back

Edited by Sqwid

Not sure how to check compression. But it seems low. Got spark. First thing I checked. Cleaning the carby now

You can pick up a compression tester for fairly cheap at a local automotive store. They are a must have for 2 stroke owners. You'll find yourself using it often, worth the investment.

Thanks for that. Found the problem. Took the exhaust off and the top end is rooted. Since I'm doing the top end I'm gonna just replace what I can over time with the money I earn. Watch for a build thread in here soon.

This was the problem. ImageUploadedByThumper Talk1381906162.820898.jpgImageUploadedByThumper Talk1381906182.840694.jpg

You clearly have a major lean condition. Might want to sort out that issue b4 installing a new piston...

My 250 came apart on me one cold'n'crisp winter day.  Little to no warm up.   It was a club race and it was a relay harescrambles and the bikes had sat all night and we weren't allowed to start them until we had the wrist band.  I just couldn't wait and wanted to catch a guy who had just left before me.  I heard it come apart and rode a couple miles back on the course (ending in a endurocross section) to the truck.  wouldn't idle and had to keep the revs up so it would have some compression to run. :D


You HAD to have heard that com apart.







Did your bottom end go as well or was that all okay when it happen?

Did your bottom end go as well or was that all okay when it happen?


Mine was OK.  It was a concern for sure.  My bits left the cylinder to the exhaust pretty quick by the amount of damage to my piston/head. 


Air is coming up from the bottom end so parts going down there is less likely than it going out the exhaust port into the pipe.  Yours looks pretty hammered.


I would evaluate your crank and decide if you want to split the case.  I did not.  You may need to but that is your call.  if the crank goes you can have bigger problems.  I have put 2 more top ends (One a year regardless of wear) in the old girl since this picture with no issues.


I know why mine came apart but you should also try and find why yours came apart or you could see this sight again soon enough.


Good luck. 

Thanks. We checked the crank and it is tight. No play at all so I'm pretty happy about that. But I have to send the head away to get resleeved as the is a chip on the exhaust port. It could be the problem or it was a fuel related problem. Which I am going to start mixing 40:1 after I rebuild and jet accordingly.

Did you change the spark plug before the pic?

It had the same plug it had when I bought it. When I pulled the plug out it was dry and had carbon build up on it.

So, black?

Yeah black sorry

Maybe it's your floats?

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