Polaris RZR Forum - RZR Forums.net banner
1 - 18 of 18 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter · #1 ·
Hey everyone, I've recently purchased a 2008 Rzr 800, I've had to put a bit of money into it, replacing parts, no big deal. It had a big gun exhaust and K&N airfilter on it, which was too loud for my liking, so I replaced that with the stock exhaust and since then it has been backfiring extremely loudly, same thing as shooting off a gun, so then I replaced the air filter with an original one, still backfires. I replaced the spark plugs, still backfires. However it only backfires when you are going less than 20km, anything faster than that and it doesn't do it. I'm baffled and can't figure out why it would be doing this. I talked to polaris dealer and they said it could be a worn clutch belt, and I also did some research and some people said the stem valve could be clogged. I can't seem to find that though, I assumed it was somewhere around the throttle body, but I'm wondering if anyone can better explain where I can find the valve and if there's anything else that could be causing the backfiring issue, thanks!
 

·
Registered
2020 rzr pro xp
Joined
·
664 Posts
If it was running fine before you put oem parts back on then my guess would be they had it tuned really rich and now you are getting way to much fuel . A fast pop when letting of throttle usually means lean and slower, random, large backfires can sometimes mean its way too rich. Loading up with fuel then igniting .
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #10 ·
If it was running fine before you put oem parts back on then my guess would be they had it tuned really rich and now you are getting way to much fuel . A fast pop when letting of throttle usually means lean and slower, random, large backfires can sometimes mean its way too rich. Loading up with fuel then igniting .
It backfired with the big gun exhaust as well but it wasn't as loud, now with stock exhaust it sounds like a gunshot going off when you're going slow and let off the gas
 

·
Registered
2020 rzr pro xp
Joined
·
664 Posts
It backfired with the big gun exhaust as well but it wasn't as loud, now with stock exhaust it sounds like a gunshot going off when you're going slow and let off the gas
Oh, then it could be any of the things the other guys mentioned then. Just gotta start somewhere and check one thing at time until figure it out. Make a list and check them off If you have too so that you aren't chasing yourself in circles. post results along the way.
 

·
Registered
Joined
·
2,588 Posts
One of two things likely. I'll start with the most likely. It has a tune or a tuner installed. Second, it has an exhaust leak. If the engine runs normally beside the backfire then I highly doubt it has mechanical issues but anything is possible. You didn't mention any poor performance issues, does it have poor performance running down the trail under acceleration ?
 

·
Registered
Joined
·
1,099 Posts
It backfired with the big gun exhaust as well but it wasn't as loud, now with stock exhaust it sounds like a gunshot going off when you're going slow and let off the gas
I was going off that the changes to stock made the issue come up as well. If it was present before those changes I would probably start with checking the valve clearances and turn the engine by hand to check for smooth transitions.
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #16 ·
One of two things likely. I'll start with the most likely. It has a tune or a tuner installed. Second, it has an exhaust leak. If the engine runs normally beside the backfire then I highly doubt it has mechanical issues but anything is possible. You didn't mention any poor performance issues, does it have poor performance running down the trail under acceleration ?
It performs great, I have no issues with power at all, idles fine, starts good etc. I didn't find no tuner anywhere so besides that is there a way I can check without tearing into the engine?
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #17 ·
Also forgot to mention, I called my polaris dealer and they said a bad clutch belt could cause it to backfire, I can't see how that would be related, but I checked my belt and it was really bad so I have a replacement being shipped
 

·
Registered
Joined
·
2,588 Posts
I've not heard that one before. Don't know if the PCM could have been programmed for the add-ons so look carefully for an exhaust leak.
since on deceleration it can suck in air and cause any raw fuel to cause a backfire.
 
1 - 18 of 18 Posts
Top