Hanging Idle - What's left to do?

So I'm struggling with this hanging idle problem that many of us have experienced at some point. My bike has done it since purchased new. It wasn't a big issue for me riding off road but I'm now spending a lot of time on the street with my supermoto setup where it's very noticable at stop lights and cruising around. I've exhausted the search feature on this topic and considered all suggestions. SO far I have:

1.) Checked for air leaks around carb boot, choke, hot start using oxygen. Nothing.

2.) Checked throttle cable tension. Good. No binding either.

3.) Adjusted valves. Intakes were a bit tight but adjustment did not solve problem.

4.) Cleaned carb

5.) Changed pilot jet from a 46 to a 48. Nothing. Then 48 to 50. Still nothing.

So what's left to check? I've spent a lot of time trying to get rid of this but to no avail.

What's worse is that my Dad just picked up an '06 CRF450 and it's jetted perfectly, from the factory. Grrrrrrr!!! :ride: I won't be able to make fun of him until his valves start going. Damn it!

I've installed the JD kit and adjustable fuel screw which I keep at 1.5 turns out, adjusting from there. 170 main. Now 48 pilot. Otherwise stock.

So can I get some suggestions?


how high is your idle adjusted? if i have mine to high, even if the motor sounds about right, it will hang when I really get on it and let off the gas, otherwise you could have something going on with the choke and cold start circuit, possible dirt that may cause it to be sticking somewhere. I would go to wal-mart or autozone and buy a bottle of berryman carb cleaner, that stuff is pure evil, and put it in the gas tank, mix it with some gas and run that for a while see if it helps. It might make the bike run like crap for a while until its all out but it will eat anything left in that carb if theres dirt in there.

Had a similiar problem with my WR400. Did most of the things you listed then took it into the shop. Got it back the the same problem, shop said they fixed by by cleaning an already clean carb and a needless pilot rejet that I immediately changed back. Problem wasn't gone though.

Anyway the problem turned out to be a rebound throttle cable that was frieghed up into the metal guide so I couldn't see it. The throttle tension was good too, I wouldn't have thought this could be the trouble but it was.

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