91 cr 125 wont idle

[Lonewolf]

on my 91 cr 125 i cant seem to get the bike to idle. i have had problems with this bike since i have owned it, it always seems to run really bad until 1/4 throttle. anyway, my service manual say they air screw should be turned out 2 turns but the bike will not idle at 2 turns at all, but it doesnt run bad to 1/4 throttle any more, i have to turn the air screw
countless times before it will idle but the then the bike runs horrible again until you get past 1/4 throttle then its runs fine. do you think that
i have a bad choke? the air screw control from idle to 1/4 throttle right? like i said at 2 turn with the air screw the bike runs good but doesnt idle, but when i turn the air screw until the bike idles the bike run horrible until you get past 1/4 throttle then its fine.

 

[Durt Cycler]

Turn the choke knob clockwise for higher idle and counter-clockwise for lower idle speed.

 

[Lonewolf]

i know that is how you set the idle but i have to turn the knob so much to get it to idle and when i finally does idle it runs awful until you get past 1/4 throttle. when i have the screw set on 2 turns it doesnt idle, you have to keep it running but the problem at 1/4 throttle is gone.

 

[DAVE C]

Clean the carb and jet it correctly. The problem should dissappear then. I would suspect a jetting problem because you said that the bike has been this way ever since you got it.

 

[Durt Cycler]

Sounds like it's too rich on the pilot.

 

[mdmader]

I have a 91 CR250 and it doesn't idle very well at all. My book recommends that you have at least 6 turns out on the choke and a turn and a half on the air screw. Also, check the air filter. If it is dirty, then you are not getting enough air for one thing. Next, try a different pilot jet. How does your plug look after a ride? It should look light brown like it was dusted with cocoa. If it is a thick dark oil, then you’re running to rich. I have an Excel spread sheet that will help you in determining the Main, Pilot, Needle, and Air Screw. It was made for the 91 CR250. I believe the 125 and 250 has the same carb. If you would like it, email me and I can send it to you.