KDXRIDER.NET

I think I have what I've heard called a hanging idle. Basically seems like it doesn't want to calm down and idle correctly. I no it's not just my idle set high, because the bike will set on idle for a little bit, then it catches it's breath and speeds up again. I am very new to this particular bike, and have made no jetting changes yet, nor can I remember what is in it. BTW 91 kdx 200. I guess my real question is what exactly is a hanging idle and where to you look for a cure? Is it sucking air from somewhere, the boots both look good, should I be looking elsewhere.

Have you taken the carb apart and inspect / cleaned it yet? That's always a good place to start.

It could also be that the pilot jet is too lean or clogged. Like Jason said, clean that thing up perfect, set the float level whether you think you should or not. Then see what it does. If you tell us what jets are in it and your altitude, somebody could probably give you an idea if its jetted stupid or not.

I would try turning in the air screw about 1/2 turn. If the bike idles ok and performs well then it was nothing more than a just slightly lean pilot jet/air screw setting.

Notice any surging when slowing down and using engine braking in 2 or 3 gear?

I'd also check for any splits or cracks in the airbox boot. Sounds like it could be sucking in air from somewhere.

Sounds like an AIR LEAK, but rip, clean and clean the carb first, then adjust

^ I would agree...

Can use WD40 or carb cleaner to find the leak while the engine is running...

I would check the manifold area, spray the area like FUZZY said and listen for a change in idle. Make sure the screws are holding the clamps tight enough. Also, clean the inside of the manifold to ensure a clean, tight fit.
Check the floats and fuel valve. Maybe something is out of whack and you are not getting enough fuel, which will give you higher idle.

If all the above fails, check the area behind the stator plate, as there are three depressions which can have a slight leak. Fredette and Gorr mentioned this area. The three areas are on 1989 - 1994 engines where the aluminum and steel heat up at different rates. The areas are suggested to be roughed up and filled in with J-B Weld or similar. Mine had a slight leak there. If you take off the cover and it has an oily mess in there, then you know it is time to fix it.

Thanks for all the insight. I will try all the above mentioned soon. It never surges on me that I can tell, and the boots both look good. I will check them with some WD, then clean my carb again.

Other things to check include the carb vent hoses (make sure they are not blocked or obstructed), the air filter is oiled and installed correctly and that the pipe/case junction is sealed correctly.

-Maurice

Thanks all.

Got it fixed. It was just my air screw. Not set right at all, as well as my idle screw. I had no leaks in the boot nor any vent lines blocked or pinched.

I've really been enjoying having a 2-stroke to rip on again, wouldn't trade my wr, but still gotta love the kdx!

Woo-hoo! I am glad to hear that you got it sorted out. Keep ripping!

Is this where I chime in with, 'I'm glad I wrote up a typically over-long and smarty pants response saying basically 'What IC said, first' (K.I.S.S.)...but it got lost someplace!!'?

Nah!

My point was, on a reasonably well maintained bike a 'hanging idle' will be likely largely due to an air screw/idle adjustment.

Glad it was simple...and that it's done!!