I'm guessing that it might not be as simple as a float level problem. I would suggest pulling the carbs off and seeing what's goin on in there first. My thought is that you probably have an air passage that is plugged up. I'm not terribly familiar with Raptor carbs but sitting for a relatively long period of time with fuel in the carbs isn't good.

I would suggest pulling the carbs off and running a little carb cleaner through any hole you can find. Do this a couple of times, a few minutes apart and see what kind of garbage comes out.

Then make sure and set your float levels properly and make sure your jetting is in the right range. The manufacturer of your pipe and jet kit will be able to tell you what the ballpark should be on those.

Hope this helps!

 

low speed = adjustable jets.
midrange = needles
high speed= main jets

check it out.

 

Before doing anything....I would clean the carbs. Get a couple cans of brake cleaner from the parts store and clean everything very well....all air and fuel passages too (especially). Take note of your main jet sizes too....did you test ride the atv before buying??