Kawasaki 220 4 wheeler skipping....

Trying to figure this one out....

Idles perfect. Runs fine up to about 1/2 rpm..... Once I go higher than that, skips bad.

Once I run it a while, it stops skipping altogether and gives good power the whole way.

I'm not sure whether it could be a stick valve or a carb problem.... Ideas?

I'd say the carb, but that seems to be the answer for everything these days. You said once it warms up it does good? Could just be an extremely cold natured motor.

I had an old Honda 4 stroke dirt bike as a kid, I'd have to run it choked out for a good 30 minutes until it wanted to die with the choke, after that it ran good with no choke.

The carb has 3 circuits. the air screw, pilot jet and main. The air screw is a micro adjust to the pilot which is basically up to about 1/2 throttle. The main jet only kicking in after half throttle. So it almost sounds like the main jet has trash in it except that it gets better. Worn cam would cause a loss of power without getting better. Valve would be the same idle or main so rule that out. Your symptoms are weird. I can usually tell you exactly by a symptom description.

This sounds simplistic, but for sure, my sons ATV will do this when the air filter gets dirty. Change it out and it's good again.... even though it does not look that dirty

Thanks for the ideas!

If the jets are partly blocked, Sea foam will fix it. But not if it is fully blocked. Yours sounds partly blocked on the main

After reviewing my thoughts... Sea Foam is not good for your motor. It changes the fuel to air ratio causing hotter combustion temps. The jets are basically metering the amount of fuel that gets mixed with x amount of air. Dilute this fuel and now you get a different burn ratio. It's called AFR numbers. In a 4 stroke, about 13 is a good number. I weld a bung on all my exhaust, temp install my air to fuel ratio meter and dial my jetting to 13 throughout the entire throttle range. This includes pilot jet, main jet, the micro air screw and can sometimes call for a needle raise, lower or a different taper needle. 14 is ok, 15 is in the danger zone and 16, you will burn your motor up. A lean burn is hot. Think of a torch. Adjusting it gets hotter based on the fuel. I have used Seafoam many times with no problem, but technically speaking, I should not recommend it.

Thanks for all the ideas.

I took it to a good shop-cause I just ain't got time to fool around.

I'll let y'all know what they figure out.