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2003 KLX 400 with 39mm FCR troubles.

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Hello guys, I've been a stalker on here for years, and just recently got a 2003 KLX 400 with the 39mm FCR. When I got the bike the starter didn't work. I bump started it and rode it up and down my street. I got a new starter, installed it, and now the bike bike starts and idles but won't take throttle.

If I start it up cold with the choke it will rev with the throttle for about 5-10 seconds then it won't take throttle anymore, it just coughs, and doesn't want to run. It will idles for days, but just doesn't take throttle.

All jetting is stock according to the manual, the bike has an FMF slip on and K&N filter, I've cleaned the carb a couple of times, changed the gas, even changed the coil, cause it was cheap. But now I'm lost.

I found an other thread on this site about this same problem from back in Sept. but the poster never posted his results if it's fixed or not.

Any help would be great.

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Install a new pilot jet. Check the fuel screw oring, confirm the fuel screw is set to about 1.75 turns from gently closed.

You also need to confirm the AP is squirting properly.

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Fuel screw is 1.75, o-ring o.k., AP is as the manual says it should be. The pilot is clean but I will install a new one. I'll give that a try. Thanks.

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When you turn the throttle, the slide raises and admits more air. If the fuel does not keep track with the slide, the mixture goes lean and the motor dies. So think about why the carb is not adding fuel as the slide goes up. I would think the fuel screw and pilot jet are OK if you have good idle with the choke off.

Possibilities:

It's too dam cold

Water in the bottom of the float bowl

Throttle valve in front of the slide is in upside down

The seal between the throttle valve and the slide is old and cracked

Quick turn of the throttle should always give you some response if the AP is working. So I'm guessing there is a problem there too.

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The weather has nothing to do with it, and there is no water in the fuel. The throttle valve is correctly installed, as far as the seal?? I'll check that. Thanks for your input.

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Sounds as if could possibly be electrical. This can sometimes be the symptoms of a faulty stator, and has been one case of this where the plug cap was to blame. Although you changed the coil i know that OEM don't supply the cap with them.

One test to see if the stator is to blame poss. is to unplug the stator plug which has the three yellow wires and run it like that. If it will then take throttle you are most likely looking at a fried stator.

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