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1990 KX 125 won’t idle

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I have a 1990 KX 125 with a full fmf gold series exhaust, and it drips quite a bit of oil from the tail pipe. I’m running 40:1, so I’m sure I’m not putting too much oil in it. Guess I need to adjust the carb?

 

Thanks!

-Luke

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Pilot jet and needle clip need adjustment.  When you get the pilot close you can dial in the air screw for ideal carburetion.

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There are times when I’m going alone and I give it some gas to accelerate and it just doesn’t want to go. Is that related to jetting?

Along*

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Pilot jet and needle clip need adjustment.  When you get the pilot close you can dial in the air screw for ideal carburetion.

How do I adjust it? Would I have to buy a different size pilot jet?

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Correct.  The needle clip can be moved up to lean out the mixture if needed but you have to swap out the pilot jet for a smaller one to lean that circuit.

The air screw is good for fine tuning and adjusting for changes in air temperature.

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Correct.  The needle clip can be moved up to lean out the mixture if needed but you have to swap out the pilot jet for a smaller one to lean that circuit.
The air screw is good for fine tuning and adjusting for changes in air temperature.

I looked up the recommendations for the exhaust I have, and it said a size 48 pilot, 3rd setting for the clip, and then for the needle it said N84k. What is “N84K” ?

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That is the specific needle they recommend for your application.  I have never had to change a needle.  Stock is usually correct or close enough to it.  Just adjust the clip position as needed.

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That is the specific needle they recommend for your application.  I have never had to change a needle.  Stock is usually correct or close enough to it.  Just adjust the clip position as needed.

Okay, thank you so much for the help!

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My KX 125 will not idle and it has oils dripping from the exhaust pipe after I️ ride it. What’s causing this and how can I️ fix it?

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