98cr 250 won't idle and bog on throttle roll on

[Hybrid]

Buddy has a 98 CR250 he recently picked up.

It doesn't idle and there is a bog when you initially roll on the throttle.

It has the stock jetting with the exception of a 190 main jet. We dropped the pilot to a 52 and still no idle but with the choke on it idles. When up to a 58 and it won't idle choke or no choke. We are going to try a 50 and see where that brings us. He can live with the no idle, but the bog when you roll on the throttle is not acceptable.

Any of you CR guys have any input here?

 

[uhlanmc]

My friends cr did that but, his main jet had fallen into the float. When I put back the main it was fine. Also it was a mikuni not a keihin. Check the throttle cable to make sure its not pinched. check the air screw, and make sure there are no leaks where the carb mounts to the reeds or air cleaner. I have one question, howz the frame on that year. I heard the 1st gen aluminum is too stiff. thanx

 

[kimoajaj]

I don`t know what the stock main jet is, but my KX250 has a 160jet, so 190 sounds big.. .

 

[toddb3]

You've probably done this already but while holding the throttle slightly open to keep it running try to adjust the air screw until the engine speeds up a little on its own then re-adjust the idle screw. Also, have you done a compression check on it yet?

 

[Hybrid]

have not done a compression test no. But we will do that. I mean its giving a symptom of a lean pilot circut, but when bumped to a richer jet it won't even idle with the choke on. The air screw seems to have no noticable effect.

I find the KX's are jetting leaner in the main circut that others from my experience. The CR250 comes with a 185 stock main jet.

 

[yz250wrw]

Hybrid - I saw your posts about repairing your KX500 cylinder. How did it turn out? Did you go with the big bore? How's it run? Please let me know.

Thanks!