Polaris 800efi 2007 losing power and backfiring - ATVConnection.com ATV Enthusiast Community

weights133 · #1 (**permalink**) 10-05-2009, 08:33 AM

Hello, all. I am new here, so bear with me. I have a 2007 Polaris sportsman 800 efi. When the bike gets hot after riding it for roughly 20*30mins, it starts to backfire and lose power. You can turn the key off and then crank it back up and it will run fine for a few minutes then start doing the same thing again. It will run fine cold, but acts up hot. I changed the air filter, plugs and gas. The bike did have bad gas in it, but has all been cleaned out and i have added stabilizer to it. The bike lost compression about 3 months ago and had to be put into shop. that problem was taken care of, and now this. I do know that there is a rubber hose coming from the top of engine and going to breather box, this hose has a small tear in it. I am trying to get that replaced. The dealership wants me to bring it in, but do to the time of year it is kinda hard to find the extra money now. Can anyone help?? Thanks

UTU · #2 (**permalink**) 10-05-2009, 09:55 AM

tear or a split. There is suppose to be a slit in the crankcase breather freezer hose (freezing weather) hose freezes causes excess pressure in crankcase.. Sounds like something getting hot and breaking down ecu,etc. Checked for any codes?

weights133 · #3 (**permalink**) 10-05-2009, 10:20 AM

I took the bike to local dealership and of course it didnt do it when they had it. It costs 145.00$ everytime they put it on the machine. There isnt any check engine lights or anything coming up in the display. But i just hate to break down and take it back to dealership, but looks like i may have to.

stendori · #4 (**permalink**) 10-05-2009, 03:46 PM

by any chance do you know what they did to fix the compression issue? alomost sounds like it could have been tight valves or something but i wouldn't think so. the other thig might be the fuel pump acting up as it gets hot it starts to break down. a few have had this happen.

deerwagon · #5 (**permalink**) 10-05-2009, 10:48 PM

Don't know if this will help. I had the same issue with my 700EFI. I was checking all kinds of things. It ended up being simple...
I brought it to the dealer. He tried everything. Finally, he happened to shine a light down the air intake in the front of the seat. He saw something and grabbed a pair of Hemos. He found a piece of the foam which goes on either side of the intake had ripped of and got sucked down the intake. Pulled the bugger out and problem solved.
Hope this is as simple of fix for you...Jeff