wow...my friends and i are stumped.my 05 700 efi backfires.Loud at times.And bogs down in the mud?Wont rev or ???makes all kinds of wierd noises.even stutters at idle.no kiddin.Also a hesitation when i give it gas in low as well.Preforms like a champ at high speed trail running.What do you all think is goin on here.??Any ideas??

 

Water in the belt would be my guess.
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2004 Polaris Sportsman 700
27' ITP 589 M/S Tires
3000 lb. Warn Winch
High Performance Dayco Belt - NEW! (on the way)

2001 Honda Rancher ES (2wd)
2.5 Warn Winch
(For Sale)

 

My first thought is the intake has a leak. Make sure the clamps and bolts are snug and no vacumn is being lost.
It that looks good, then it probably the throttle position sensor is out of adjustment or broke.

 

My best friends 500ho was also backfiring. He took it in when I was getting some maint. done to mine and all they did was right there at the throttle where th cable comes out, push the rubber boot back and tightened the twist screw with their hands. Then pushed the rubber boot back over the cable. They said it was a common thing. Try it....

 

Thanks guys,Ill try those things,but it was really wierd.It ran amazing at speed but at slow speeds it really hesitated.At one point in the mud i could not throttle up enough to turn the tires!Would just cough and sputter and cut out??Very wierd.Im tryin to get to the dealer this week.we'll see what they have to say.

 

I'd say its the tps sensor on the throttle body, just had mine replaced on my 04 it didn't want to idle properly, but still ran good when at full throttle. Take it to your dealer and have them check it. Should be warranty.