My 2006 Sportsman 500 HO works fine for first 10 to 15 minutes then starts to hesitate on acceleration.Works fine at low speed and at high speed, but skips bad at around 10 to 20 MPH.When I accelerate from low speed to go up hill or just to increase my speed the engine skips bad.When I really give it the gas it picks up and runs fine at the high speed.Starts and idles without a problem.

 

Have you checked into the carb as far as trash,etc that may be partially stopping up the jets? Plus could be water in the system?? OPT

 

Bike is EFI.No jets.I emptied tank and cleaned it.Going to remove map sensor and clean it.

 

Since it's an efi one of the most common problems is the map sensor harness and connector not the sensors.Check the small wiring for any cuts or soft spots in the wiring. They can break internally and can cause intermittent problems also. Look at the "sticky" above the expert section on efi wiring problems. Also not a bad idea to check the fuel pressure at the fuel rail.Think it should hold 33 psi on the 500 efi? Plus it wont always throw codes on problems like this. OPT