Hi guys, Been a while since i posted but have been reading. We just got back from a 250mi ride in iron county WI a few weeks ago and noticed that my 2005 sportsman 500 would sometimes backfire on deacceleration. Before, it would happen once in a great while but this trip it would happen 10-12 times a day. The ATV has about 1800 miles and 100+ hours. I have adjusted the valves this winter and only had to make a very slight adjustment. It isn't running hot or anything and runs really good. just backfires. Any ideas what is going on and how to fix??? Thanks for your help everyone!!!!

 

Sounds like a prb Im having to right now with my 2004 600.

 

Is your valves set to .006"

Check for any exhaused leaks or cracks. Does the ATV idle low or stall? If so you have to adjust the ETC switch.

heres a video on what it does and how to adjust it. Polaris ATV Thumb Throttle Maintenance Tips: Polaris ATV Maintenance & Repair Tips | eHow.com

 

I have checked the throttle linkage for the ETC adjustment and there is very little slack. As far as the Valves I adjusted according to my service manual and .006" sounds correct. I do remember one valve had a dab more gap than .006 so I had to tighten it down slightly to get to .006, otherwise there was very little adjustment needed to the valves. I didn't see or hear any cracks in the exhaust or intake anywhere. The machine idles just fine. Also before our WI trip I did put in a new air filter and cleaned the pre-filter. Keep the ideas coming guys! Thanks again!!!!!

 

Hi guys! I worked on my 2005 SP500 HO (Carbureted) some this weekend. I checked all the grounds and they seem to be good. Rechecked the ETC and it’s good. Tried to find any exhaust leaks by looking at all the exhaust connections and it all seems tight. Also, when I put the exhaust system back together again I held my hand over the exhaust to build pressure in the exhaust system and could not find or hear any leaks. Took it down the road and got her up to temperature, went over a hill accelerating at full throttle and once I crested the hill I let off of the throttle and let the EBS do its thing. After about 3-4 seconds it backfired again just like before. Do you have any good methods to check for exhaust leaks???? Can I use high temp caulk to help seal up the connectors where the springs are located? I'm thinking this has got to be the issue. Thanks guys!!!!!!!!

 

I jsut always thought this was common with EBS

 

Its running too lean, take the top off the carb and lower the e clip on the needle one notch this will make the mixture a little richer and should solve the problem.I guess its a carb model?