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Bike idles fine except for when warm?

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My 2 stroke ktm 200 will idle fine when I start it up and let it warm up for 3 minutes then when I take it down the road and try to let it idle again it's really low idle for 5 seconds then stalls out. What could be the problem? Could it be a wrong pilot screw adjustment? I haven't tried to play with that yet. Also it seems I'm running a tad too rich. Should I turn the pilot screw in or out to try to help this? I do realize it could probably use re jetted

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If you think its running rich, turn the air screw out, more air. Adjust the idle speed screw to increase idle.

Using the "whack the throttle " method to get the air screw tuned close works well and is easy to do. Basically, warm up the engine, then quickly open and close the throttle and take note of engine response. As you turn the air screw in, you richen the mix. You are able to quickly determine if response is getting better or worse. If worse, come out with the screw, if better, keep going in with it. 1/8 to 1/4 turn at a time.

Where the screw ends up when you find the best off idle response will tell you if you should go with another size jet. Less than 1 turn out = bigger pilot jet, more than 2-2.5 turns out = smaller pilot jet.

And general concensus is, you don't let a 2 stroke sit and idle to warm up. That's a good way for it to load up and foul plugs. As soon as it will run without choke, ride it to warm up. If you don't ride it, at least sit there wicking the throttle open regularly.

Edited by Trailryder42

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If you think its running rich, turn the air screw out, more air. Adjust the idle speed screw to increase idle.

Using the "whack the throttle " method to get the air screw tuned close works well and is easy to do. Basically, warm up the engine, then quickly open and close the throttle and take note of engine response. As you turn the air screw in, you richen the mix. You are able to quickly determine if response is getting better or worse. If worse, come out with the screw, if better, keep going in with it. 1/8 to 1/4 turn at a time.

Where the screw ends up when you find the best off idle response will tell you if you should go with another size jet. Less than 1 turn out = bigger pilot jet, more than 2-2.5 turns out = smaller pilot jet.

And general concensus is, you don't let a 2 stroke sit and idle to warm up. That's a good way for it to load up and foul plugs. As soon as it will run without choke, ride it to warm up. If you don't ride it, at least sit there wicking the throttle open regularly.

Wow your the person I needed to talk to!! That helped a lot and made sense. What was happening is to let the bike "warm up" I would let it idle for about 2 minutes and when I hit the throttle after that I found that it would smoke a lot so I was thinkin that from idling the cylinder was filling up with fuel that wasn't being ignited. I will try that. So when I kick the bike and get it started maybe let it idle for 10 seconds then keep blipping the throttle in short twists for how long till I should hop on and ride it?

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I'm usually waiting on friends, but generally, after I turn the choke off, I sit there wicking the throttle for less than a minute then I take off, ride around easy to be sure its running clean. Then its good to go.

I don't agree with those that say to start it, turn off the choke and then flog it. It's too easy to get differential heating. If the piston expands due to heat before the cylinder has a chance to catch up, its possible to have a seizure.

Edited by Trailryder42

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I'm usually waiting on friends, but generally, after I turn the choke off, I sit there wicking the throttle for less than a minute then I take off, ride around easy to be sure its running clean. Then its good to go.

I don't agree with those that say to start it, turn off the choke and then flog it. It's too easy to get differential heating. If the piston expands due to heat before the cylinder has a chance to catch up, its possible to have a seizure.

Thanks for all your help man. Ride on

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