i finally jetted my sons trx 250x. it was idling perfect but was lean on between 1\4 to 3\4 throttle so i went to move the clip on the throttle needle. it was already at the richest setting so i put the carb back together and when i started it back up i lost the idle. i mean no idle speed at all. if i turn the speed screw it has very little effect. this is the second time this has happened when i open up the carb to adjust the needle i lose the idle. i have it running very well at speeds above idle (main jet from 28 to 38) turning the idle mix screw has no effect good or bad. it is like the idle circuit is missing. any ideas?
thanks dan

 

More background information would probably help. Have you done a plug check? What color is it? Is the ATV totally stock or is it modified? If modified exactly what has been done to it? If it's 100% stock I can't see why it would need/be at the richest jetting location on the needle unless something else was wrong. I don't think I've ever heard of a stock ATV needing the richest needle setting...

Anyway, based on your last line, my initial thought is that it might possibly have an air leak. To check for a leak, hold the throttle at a steady RPM. Hold it at as low as you can where it will stay running. Spray some Carb cleaner around the carb area (manifold, top Etc). If it's leaking you should hear a change in the RPM's.

Rude Dog