1993 RM250 Won't Idle!!! Please help

[ssk250f]

Hello All,
I am new to the forum, and before i go on with my issue i just want to say what a world of knowledge this site is. Just from reading the current forum topics/discussions I have picked up on so many things, you guys really have a great thing going here.

So we have a 93 rm250, just bought the bike for 700 bucks, ran good on the day we bought it, put about a half a day of real riding on it and now it wont idle at all. Not with the choke up, not without the choke, the idle screw does nothing to raise ot lower the idle (if you know the carb its the one that has the idle screw built into the choke pull knob) the air mixture screw does nothing as well.

I opened up the carb and gave it a complete rebuild and still nothing. Suspecting the bike needed a top end i did a compression test and the highest reading i got was 110psi.

Is it possible the piston/ring are so shot that its effecting the adjustments screws from doing anything?

Any suggestions/help would be so much appreciated.

Thank you in advance,
Shaun
:yikes:

 

[chris121277]

I have the same bike, same year and mine does the same thing....so just wanted to tag along here and see what they say.
Chris

 

[ssk250f]

I have the same bike, same year and mine does the same thing....so just wanted to tag along here and see what they say.
Chris

What have you tried or heard from mechanics so far Chris?

 

[chris121277]

So far everyone keeps telling me that I have an air leak some were. I have checked all the places that It could be leaking but haven't found anything.
What do you have your Idle/choke nob set at......I've found that if I don't have it cranked almost all the way closed that the bike will fowl plugs like crazy (and I mix 50:1)

 

[2strokerfun]

Your compression is getting pretty low. Did you test it when it was warm or cold?
As you suggested, a worn top end can contribute to this. A worn jet needle or a worn slide in the carburetor can also cause this problem. I'd suggest taking off the cylinder and inspect and measure the bore, piston and rings. If worn beyond service, rebuild the top end and you can then start eliminating other issues if the problem continues. All the jetting work in the world isn't going to do much long-term good if your top end is worn out.