This is my 1st post here. I tried looking around to see if I could find a post similar to this one but no luck. I have a 2000 Polaris 500 Sportsman (non HO), when I give it gas it boggs down and then makes a popping sound in the air box. It gets worse going up steep hills or in mud. Originally I thought it was spark related since I had a crack in the spark plug boot. I replaced the coil/wire still no change. I then took the carb apart and cleaned the jets, still no change.

 

have you tuned the carb and set the floats correctly

 

I really don't know how to tune the carb past removing and cleaning all jets. I should have originally stated that it was running fine we went on a ride and half way through it started doing this. I have also changed the fuel filter, air filter and prefilter.

 

sounds like your pilot jet is clogged. locate it and clean it up

 

how many miles on this? i know some of the older 500's had weak cam's and it would round off the lobes making it have to power/back fire. just an idea

 

Have you checked the plug to see if your running lean or rich?
Water in the gas?

 

more than likely its your cam, one or both of your cam lobes are gone as stendori says.

 

I checked the plug and it is running lean. I also removed and cleaned the pilot jet again. It has about 1300 miles on it. The one thing that I did overlook the 1st time............I found the wire (blue) to the therostat switch was broken off. To my knowledge this should not have anything to do with it right?

 

If you have checked/changed/cleaned the air filter and checked the fuel vent line then it sounds like a cam problem.

 

Sounds like it's going to go to the shop. Is there any chance that it could be in the diaphraghm fuel pump? That is the only thing left that I have not checked.