My friend wants me to jet his son's 80 because he installed a FMF Gold seiries pipe on it. I was wondering if anyone could give me instructions to changing the main and pilot jets and moveing the needle? Is it the same as you would on a dirtbike or YFZ450; take off the 17mm nut on the bottom of the carb and the jets are rite their? Is the needle accesed through the top of the carb?

In other words please post step by step instructions on how to jet a KFX80.

 

You must remove the carb and take the 4 screws out to remove the bowl. No big hole like other carbs.
Yes the needle is accessed the same as others.
Why does it need a jetting change? What's the plug look like?
FYI: they come jetted very fat. To rejet you will go DOWN in jet size. Prolly a 87.5 or 90 will do it.

 

I'm at about 4000ft.

do they have pilot jets also?

What is the stock main?

I have not seen the plug but he said it idles ruff or does not idle at all.

Do I need to change the needle clip position?

Thanks for all of your help.

 

Yes they have pilot jets. The stock pilot is either 17.5 or 20. Stock main is 92.5
I wonder if all that is needed is the idle screw turned in?!
Your welcome. Happy to help. [img]i/expressions/face-icon-small-smile.gif[/img]

 

I'm close in elevation to you and I went with a 87.5. I didn't mess with anything else other than the main jet.