That has got to be it. I'm glad you posted this cause I've had mine since july 07 and it never done it until the last few rides it has done it 4 times now. A couple months ago I installed the new big air filter. That is the only thing I changed on it. Did you put a prefilter on it?

 

No just the filter.

 

Mine does too. And it didn't when it was new. I've also got a different filter. Odd...

 

normaly its a ex leak but 3 of you with the new filter???? could be running a tad ritch or lean....

 

OK here's where it gets wierd! My RZR has ALWAYS smelled rich to me, especially at idle. If I am trail riding and not going very fast, and the fan has to run alot the header gets glowing red hot (lean condition). I don't know what to think, it runs great and always has.

 

my gibson exhust backfires after i floor it for a while. i have a wideband o2 sensor and i am not running lean, if anything my mixture is at 12.5%. 13% is what is recommend for NA engines. everyone trips out behind me, they say i am like a lemans car taking turns

 

Mine did it too when I just had the UMP air intake on it. It was only after WOT, soon as I let off the gas it would go POP! Then after noticing my head pipe glowing, I also noticed the panel between the passenger and the engine had melted almost all the way through.

After hearing that all that extra air is causing a lean condition, I was scared into buying a fuel controller and an exhaust. $900 later, no more pops, the bed doesn't even get warm enough to warm my gloves up.

 

Usaully when engines do that its because it has A exhuast leak or you have A short exhaust pipe or large diameter pipe

 

Get a PC3 and you will be good to go, for a prefilter on the new style air filter
I used a knee-high nylon from my wife.
Nice of her to contribute.epper1:

 

Get a PC3 and you will be good to go

PC3 ??? fuel controller?

 

I dont know what its worth but I was with my freind the other day in his rzr and he said it has been backfireing since he had been using Caseys fuel. Theis station sells an ethanol bend around here, I think it is 89 octane and a 15% blend.

 

backfiring is usually a condition casued by to lean of a fuel mixture. When you let off you gas you will go lean for a bit and when you use ethonal gas you are going to run leaner. It is oxigenated fuel.

 

All gasoline in Oregon at the pump by law is oxygenated fuel as of Jan. 2008 I believe. The only exception is at boat marinas. All the gas I have put in the RZR has been from the gas station, so it is oxygenated.

 

A friend of mine has been running lean since he got his. He put the new filter on, and it got REALLY lean, and backfired a lot. Header pipe was blazing hot. New fuel controller is being installed. I think they measued his air-fuel ratio in the high 14's.

 

the fact that some have to run oxegenated fuel is probably why you hear so many differnt thought on whether they are to lean or to rich from the factory.

 

Hey Jeff --

When you run Winchester - Buy your fuel from the Boat Marina. It's Hi-Octane -- No Blend !!

This is where I get mine from - They will fill any size gas/fuel approved type of container.

You might have to wait 10 minutes or so after you press the buzzer -- They are extremly friendly and glad to help.

Dave

 

Yes I am aware of that, infact I know the people that work there. It says in your owners manual to only run regular unleaded so thats what I run. My buddy buys his gas for his YZF 450 quad there when we are in Windy Bay.

 

oxygenated fuel will run way lean. backfire on decel is also lean. i was running rich on my rzr untill i got the gibson

 

a ritch condition can also cause your head pipe to glow not just lean plus with the tight bends coming out of the head and night they do glow a nice fire red.....you should see my quad after a few races....one guy lit his cig with it....lol

 

My 08 rzr is doing the same thing. Backfire when I get off the juice. I have a Dragonfire racing G3 fuel controller that was supposed to take care of the pop but perhaps it is set up wrong?? Anyone have the controller? Any advice. The machine was built before I bought it and I'm not sure how it would be set up. It's cold here right now and maybe that plays a part too?? Any help would be appreciated.

 

its too lean the bigger air filter is letting in more air and causing a lean condition needs more fuel to gain power and get rid on lean pop

 

Bigger air box added with colder air makes lean also

 

Shouldn't the damn EFI take care of the Lean condition on it's own? Isn't that suppose to be a big selling point for EFI.

Jim

 

nope thats why they sell pprogramers to fix the problems you cause by adding exhaust and air filters

 

Without an O2 sensor for feed back data it uses a program set up based on rpm tps baro and map sensors and such.
I have recently installed a wide band O2 sensor bought used from a member here.
Also added the Power Commander Ignition module, nice to know I am not running lean
now.

 

its too lean needs more fuel