A friend and I both bought sportsman 850xp the same day 2 weeks ago. Our problem is they both are backfiring. They only do it after you accelerate hard and then come back to an idle. Besides that they scream and we have no complaints. Anyone encountered this or have any suggestions? Our dealer said the throttle cables may need adjusted. I cant see this causing this since they are fuel injected and all.

 

Listen to your dealer..he is right,the throttle cable adjustment should be the first thing you try...
The adjustment has nothing to do with the EFI really..it is adjusting the ETC(Electronic Throttle Control) which is just a big name for a safety feature that will basically shut down the engine in case of a stuck throttle..it senses slack in the throttle cable..if the cable is just slightly too loose it can intermittenly activate when you quickly release the throttle.
The procedure is simple and is in the owners manual..look it up read it over and let us know if you have any questions..

There are other things that can cuase the backfiring..but the cable adjustment is a common one and is the easiest to check.

 

Make sure your dealer installed the new hotter plugs & updated the ECM. This won't completely rid you of backfires but it will run a whole lot better

 

I took my 850 xp out for the first time today and it backfired also. I know it needs the ECM update. It was built in mid Nov by the build sheet. There is a sticker behind the radiator dated mid Sept. Either way it needs the ECM and plugs.

 

This problem has been happening since they first came out. The THROTTLE CABLE NEEDS TO BE ADJ.! The ECM update and plug change are ok to do but they are not the cause of the backfiring. IMO!
The dealer is right!
Good luck and have fun!
Oh and Welcome to the forum icer97!

 

My machine was built Sept 18th,I have not had the update done and I don't have any backfiring..
I make it a habit of checking/adjusting the throttle cable at lesat by the time I do the 1st service,then after the machine is broken in and I have stressed the cable by going WOT several times. The new cable will stretch a little, depending on how it was adjusted from the factory that little bit of stretch could be enough to itermittenly activate the ETC when you quickly let off.
I know of at least one person who had backfiring and got the updates..he still has backfiring..he has not checked the cable adjustment yet..
Even if it is not causing the backfiring in every case improper adjustment can cause issues and it is an easy thing to check and eliminate.