2005 MXZ Renegade backfire issue

[OwenKinley]

I have a 2005 Ski-Doo MXZ Renegade. It runs fine but the only problem is that is has a very loud backfire. It seems to backfire every time it decelerates from 4k rpm. It doesn't matter weather its cold or warmed up. Not sure if this is important but when decelerating - even when off the throttle - it will sometimes hold the rpm at 4k until it backfires than it will come back down to idle. The sled has just over 3000 Miles. Another problem is the kill switch does not work, I'm not sure if that could have anything to do with the issue. There does not seem to be a lose of power.

I appreciate any help,
Thanks

 

[Ox]

Well, a 2005 Shirley isn't a "Zx" model, so you should be up one categorie, but anyhow...

I've never had them backfire while running, just if shuting them down (killing it) too quickly, without letting them idle all the way down.

Maybe you wunna check your plug colour?