backfire

[MNApexRider]

Took out the new to me sled 2 weeks ago. Was Awesome. Everything was great except, track was a bit to loose and I had a couple backfires when slowing down. Bought new copper donuts and also 4 new flex pipes just in case. Took it all apart over the weekend. Already had copper donuts that looked great and the flex pipes looked great, no cracks. The clamp bolts holding the header pipes to the muffler pipe were both VERY loose. Thinking that was more than likely my issue, cranked them down, put the flex pipes back on and put it all back together. Also noticed the OEM muffler had been cut open and welded shut, I assume it has been gutted. Well, out on the trail, it still backfires. Are there gaskets from the header pipe to the 2 into 1 muffler pipe? I would have to drop the skid to get a better look, but if its not hurting anything I may just ride it out for the winter and deal with it in the spring.

 

[steiner]

There are gaskets where the Y pipes meet the muffler pipe. I ground down the shoulders of the flex pipes clamps about 1mm or so to help keep them tight when I did my copper donuts. Double check your flex pipes. They are sleeved which makes it difficult to determine if they are cracked or not.
Really can't see the gutted exhaust being your backfire problem. I ran a Excel system ( basically a straight pipe) for years with no backfiring

 

[sideshowBob]

Definitely sounds to me like an exhaust leak somewhere as well. Like steiner, I also ground the clamp sleeves down a bit to allow the clamps to tighten up more..
I once had a Bender exhaust on my Apex and it cracked just where the pipe meets the canister and it caused the sled to back fire a bit.

 

[kinger]

Quick way to check for leaks is start sled and with a glove on cover both exhaust tips. If it dies you’re good if it keeps running you have a leak. My guess is that your exhaust is cracked somewhere.