I have a 2004 kfx 400. I just bought a power up kit off e-bay and I need some help.
After I installed every thing their is alot of poping and even some sparks when I hit the gas.

It was a dyno jet kit, it told me to put the clip on the third setting and install the 150 main jet. The one 150 main is the biggest main that was in this kit. The old main was a 130 I guess thats stock not sure.

The kit also told me to turn the air mix screw all the way in clock wise than turn it out 3.5 turns counter clock wise. I turn it 3 full turns than one half turn.

The kit also cam with a oiled filter and a pre filter made of foam that gose around the oil filter than it has a filter cover tha gose over it but I could not get it on because it looks to be to small.

I pulled the snorkal out of the air box but Im not sure if I was supose to and I took the air filt box lid off. I followed the stage 2 instrutions to the letter. I do have a after market muffler on it so thats why I did the stage 2 install.

Can anyone help me line this out? The atv starts wright up, I have not rod the atv yet because I live in town and the dam cops would come if I rod it down the street. I know that its not jetted wright so any help would be great.

 

Start by checking your spark plug see if it is a golden brown or a wet black color if it is wet and black then yes it is proably getting to much fuel you want to get it to where your spark plug is a golden brown color it may take a little bit of work and changing out jets but eventually you will get it right good luck