Backfire Issue

[SeX Viper]

My 14 RTX developed a backfire this season and I am wondering where to start. It starts and runs fine, it only happens at low speed like going through town. If you coast to a stop it will not do it. I can make it do it almost every time if you are coasting to a stop but fall a little short and give it a little more while coasting to make it to the stop sign. When going slow through a town or into a gas station it is pretty constant when letting off the gas, it is basically impossible to ride slow and not have it do it. It does not do it however when you first start out, it only starts happening after you get it fully warmed up and ride for several miles. It has never flashed a light and the dealer said there are no codes.

I bought it non current and it is still under warranty. I took it to the dealer and and they cannot make it do it on a stand and have no way of test driving it so they said bring it back in the fall. I pushed them a little to look further but they said without having it happen to them they cannot narrow it down as to what to look for. As much as that frustrated me I understand they cannot justify spending a lot of time on it if they do not know what is wrong but I do not want to start my season next year with a broken sled. I am going to pick it up tomorrow and will be changing the oil, chain case fluid, and pulling the skid for its annual once through and am wondering if there is something I should be looking for. They said if I find a something wrong bring it back and they will take care of it. I am guessing the exhaust is broken or cracked somewhere, just wanted to see if anyone else has been through this before I spend too much time taking it all apart. I did try new plugs mid season and that did nothing. I rode it this way for 1500 miles, it didn't get any worse or better at any point.

 

[MrSled]

Check to see if the header pipe is broke or the flex joint.

 

[cannondale27]

Yup or the whole can may have split.

 

[Mike P]

Had the same issue, 14-RT X with turbo. My problem was in the header. Almost 13k miles. I think I got my use out of it. Not only did it back-fire but it was extremely loud as well.

 

[Mike P]

My solution was to upgrade;

https://www.straightlineperformance...arctic-cat-7000-series-full-stainless-header/

 

[SeX Viper]

If the exhaust is broken somewhere I don't think it is to the same level as Mike P as it doesn't sound any different than stock.

I changed the oil last night and when I pulled the muffler off you can hear liquid (I assume gas) sloshing around. I inspected the exhaust the best I could and could not see anything broken. What is involved in taking the gas tank off so I can see everything? I already have the skid out, hood and seat off, it looks like you just have to take those two tubes off that angle up from the tunnel to the steering post.

 

[hognit09]

Yes, those 2 frame tubes, and the exhaust shield. Not sure if gas tank can be removed tho without pulling some of the electrical that goes back to battery and fuel pump

 

[MrSled]

Remove seat, disconnect battery, unplug a tail light and few other electrical connectors, disconnect fuel line, cut a few zip ties and removed 2 down tubes, and remove the gas tank. Remove tunnel/tank heat shield that covers the header.

 

[SeX Viper]

Well I got it all apart and the exhaust looks great, I do not see any signs of cracks or broken welds.

 

[MrSled]

Did you check on over the seam really good? Or the manifold gasket?

 

[74Nitro]

Yup or the whole can may have split.

Yes, a friend of mine had a 14 and the muffler cracked open, sled almost caught on fire.

 

[cannondale27]

Yes, a friend of mine had a 14 and the muffler cracked open, sled almost caught on fire.

Yes it was quite common.

 

[SeX Viper]

I checked and rechecked the exhaust and I do not see anywhere that it could be leaking. I even stuck a high power flashlight in it at the joint and looked for light coming out of a crack in the dark and did not see anything. The gasket is metal so I do not see how that could go bad, I used a mirror and looked all around the flanges and do not see any discoloration on the block which I would think it would have if the exhaust is leaking. I also put a socket on the manifold bolts and they are all tight.

After thinking about it more it makes sense that it will not do it until I ride it for several miles because the muffler needs to get warm enough to allow the fuel to burn. The only reason I can see that fuel is accumulating in the muffler is that it is either getting too much fuel from a bad injector or it isn't burning the fuel due to lack of spark. I did change my plugs at one point this season and they looked good and the sled never feels down on power at any point.

I was really hoping to find a cause so I could get the dealer to fix it before I put it away for the summer but I guess it will have to wait. At least it is still under warranty I just hope I don't end up in and out of the dealer all winter with them chasing their tail.

 

[Norse]

Did you uninstall the header? See any black spots anywhere around the exhaust system? Check spark plugs condition? Cover up the "tailpipe" and see if exhaust appears elsewhere or if the engine dies?

Mine suddenly lost all power but I had a big crack in it so I installed the SPI header. BUT I get this coughing/backfire noise sometimes and it always leads me to a leaking intake. Check your throttle body hoses.

 

[Hibb Viper]

I checked and rechecked the exhaust and I do not see anywhere that it could be leaking. I even stuck a high power flashlight in it at the joint and looked for light coming out of a crack in the dark and did not see anything. The gasket is metal so I do not see how that could go bad, I used a mirror and looked all around the flanges and do not see any discoloration on the block which I would think it would have if the exhaust is leaking. I also put a socket on the manifold bolts and they are all tight.

After thinking about it more it makes sense that it will not do it until I ride it for several miles because the muffler needs to get warm enough to allow the fuel to burn. The only reason I can see that fuel is accumulating in the muffler is that it is either getting too much fuel from a bad injector or it isn't burning the fuel due to lack of spark. I did change my plugs at one point this season and they looked good and the sled never feels down on power at any point.

I was really hoping to find a cause so I could get the dealer to fix it before I put it away for the summer but I guess it will have to wait. At least it is still under warranty I just hope I don't end up in and out of the dealer all winter with them chasing their tail.

I know this is an old thread, but I am having the exact same issue and I've been pulling my hair out over it. Did you ever end up figuring out what the issue was. Was it a bad injector like you thought or was their an exhaust leak somewhere? Any feedback would be greatly appreciated.