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Hi guys I'm hoping somebody might be able to help me here. I've been riding my kdx hybrid (03 rm125 with 02 kdx200 motor) and my throttle keeps getting stuck wide open. It doesnt feel like the cable is sticking. And I've tried two different stock used carbs. And two throttles and cables and it does it on both. Seems to only do it when I'm in the powerband. Could it be anything to do with the power valve? Or anything else? Thank you any help is very appreciated

I would check the simple things first. Cable routing and condition of the return spring (if it gets hung up on anything).

Did you try with a new cable or two used ones? It may seem trivial or unlikely but who knows

Thank you very much for your input. I made sure the throttle cable was placed so nothing can rub against it. And it only happens when I'm riding it. I can twist the throttle for hours and it will never hang up

First, it will have nothing to do with your power valve. They are completely two different and separate systems.

Now, are you saying the throttle (where your hand goes) physically will lock up and not move?

No the throttle does not seem to be getting stuck at all. It seems more like a lean runaway type of thing. But I dont see why I would have a problem with both carbs. I never had a problem with it before. I also did a leak down test with no issues

If you have a problem with two carbs, then that makes me wonder if it is something else.

So to summarize:
-throttle sticks but only when you are "in the power band" by that I'm assuming you mean, hard on the gas?
-does it with 2 different carbs (same slide or different slides also?)
-also tried different throttles (assume you mean hand twist grip assemblies) and different cables
The only thing I see in common off hand is how you have the cable routed. There are only three moving parts, throttle/grip assembly, cable and slide.
If your throttle is sticking, it has to be one of those 3. Something is holding the slide up. Can't get a run away (stuck) throttle otherwise.Mine stuck once and I found it to be the cable stuck under the tank. I'd recheck the cable routing again and use zip ties to make sure it can't move around.

I would check throttle cable routing & also throttle housing again.

Thank for your input guys. It doesnt feel like the throttle is actually sticking. The bike just stays revved up after I let off the throttle somtimes. I zip tide the cable where I know it is not rubbing on anything. And yes I've used Two different twist throttle assembly's and slides. I have a new carburetor coming in the mail. I will let you guys know how that works out. Thank again!

Just a thought have you checked the rubber carb holder for leaks?

rungrandpa wrote: ↑09:14 pm Jun 18 2019 Just a thought have you checked the rubber carb holder for leaks?

I was thinking about this thread earlier today and thought about this.

Maybe this leak isn't exposing itself until you're really sucking in some air ?

Freezing up ?

I sprayed it with starting fluid when it was idling and it did not rev up at all. But that is a good thought. I will look into that!

Still sounds like a carburetor issue to me.

Just throw it away

Try giving it some throttle when spraying to try to replicate conditions as best you can.

Thanks guys. It ending up needing crank seals. Bike has no issues now!

masonkdx200 wrote: ↑07:40 am Jun 16 2019 ...I also did a leak down test with no issues...It ending up needing crank seals...

You might want to recheck your leak down setup if that is the case, it should have caught that and would have saved you considerable time troubleshooting.

Congratulations on getting it figured out. Enjoy your KDX!