Not sure exactly what forum to put this in. Ok so this coming up weekend we are supposed to be trail riding and i cannot figure out my daughters quad. Its an 05 polaris predator 90. Ran great few weeks ago then went down hill. It fires right up, but as soon as u go to rev it spits and spudders and backfires. Its worse when its warm. I put a new carb on, new stator, new plug, new air filter. Also i seen on youtube to remove the 2 screws for the rev limiter. I did that. Still having same issue and im pulling my hair out! What else could it be?? Thanks in advance

 

You could also post it i the polaris section. I don't know a ton about polaris, but all quads are similar.

So you already checked out the carburetor, which is the most common problem. My first guess would be that there isn't enough gas coming in. You should check along the fuel line. To test of the gas is coming out at all, you should unconnected the tubes that bring the gas from the tank to the carburetor. Then fire it up and see if any gas comes out.

I would think it is something to do with gas, but if its not, my only other guess would be the air plugs on the top of the carburetor might not be good, or might not be on right.

Good luck, let me know what you find out/updates

 

Seems you've replaced everything but what does compression show? Could be loosing ring seal against the cylinder when the engine warms up if compression is below 100psi.

 

Did you ever figure it out?