1990 KX 125 won’t idle

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

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

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*

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?

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.

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” ?

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.

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!

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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