I have 2 550 and after they warm up a little and you let off the throttle they both back fire one more than the other. I put new spark plug in them and that seemed like it helped alittle, or do they all backfire?

 

how did the plugs look, wet black, or maybe white looking?

 

adjust your throttle free play.Sounds like your etc switch is making contact when you let off throttle.that will cause xp to back fire when you let off throttle.your owners manual will tell you how to adjust free play.xp are adjusted differently then other polaris etc switches.

 

the plugs looked like new

 

I will have to check the owners manual and do that. I called the dealer i bought them for and they said it is something the 550's do.

 

sounds like thier running lean

 

What Ramman said, All it is the throttle cable play is not right. Read your owners manual it walks you thru it to adjust. Have had this problem with my xp's dont be alarmed

 

Thanks for all the advice.

 

I will have to check the owners manual and do that. I called the dealer i bought them for and To this, I call a big BS. Lazy dealer. Mine has never done that.

 

what a joke dealer I would not buy anything from them again. You pick the dealer that is willing to help you next time not the joke that blows you off.