I just got done changing frames out on my 2003 Honda 250 EX. The quad ran perfect before I put everything on the different frame. Now It idles very high and I can't get it to idle lower. The only thing I messed with was unscrewing the spring loaded throttle assembly from the top of the carb. I thought I put it back the way it came out but maybe I didn't. Anyone with answers would be appreciated. Thank You. Also where are the adjusting screws for the air and fuel on this carb? Sorry about the mistake. I had orginally said 300 EX. It is a 250 EX.

 

Okay. I seriously am not trying to be a smart buttocks. So there's this idle screw..... Also, check your cable and make sure the throttle has play. Does it idle up when you turn the bars? Lean mixture can also make for a high idle. Air leaks? Good luck.

 

I have tried turning the idle screw but it doesn't seem to help. I did not know there was a throttle cable adjustment. I know that I can take the cable where it screws into the top of the carb and turn it and it does have an effect on the idle. I would say you might be right about the play in the cable. There is no play in mine. I just assumed if I put it back the way it came off, it shouldn't have changed anything. How do you adjust the throttle cable? Thanks for your help.

 

there should be some screw-justments on the thumb throttle assembly and on the carb I believe. I thought you said something about the carb cable adjustment though. It sounds to me that if you didn't touch anything, it should be fine. (assuming the same throttle assy. and carb) ....so maybe a cable end came un-seated from a screw-juster, or somebody was just absent-mindedly playing with the throttle cable end adjusters.