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!
Backfiring issue 08 Rzr 800
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With all those bolt ons, did it have a tune added?
I'm not sure if it had a tune, is there a quick way I can check that?
The spark plug and exhaust system is all goos but I have not checked for a valve sticking (what valve would that be?) And I have not checked Ignition system
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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 .
Look too see if it has one of these. Most people just ran piggyback fuel controllers on the 800's.
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.
Do you
Do you have or are able to get me a diagram for the stem valve? I assume it's near the throttle body, I've looked for it but all I've been getting is the valve stem for the tires, which I obviously don't need lol
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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 ?
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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.
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?
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