I have a 06 Polaris Sportsman 500HO EFI. When it get warm I am having a hard time keeping it running and starting it again after turning it off. I changede the spark plug and put high test gas in it and still am having the problem. any suggestions?  

I finally figured out the problem with my Quad.  The problem was a clogged fuel injector. I added Berryman's Fuel Injector to the gas and ran it for about 10 minutes very hard and it is running like the first day I got it. Thank God it was a $4 fix.