engine miss/back popping

[azpnshr]

I debaffled my exhaust about 2 weeks ago and up until now, no problems have been experienced. Today, I went for a ride and fired her up. It sounds like the engine is missing at idle. Took her for a spin and it sounds fine when maintaining speed or decelerating; however, under load of accelerating, it sounds like the engine is missing. I also noted that when shifting, the exhaust seems to be popping, possibly due to back pressure.
I don't have a lot of experience of mc engine works (never had many issues either) but it seems similar to sounding like an exhaust leak on a car. I'm taking it into the stealer tomorrow, as its still covered under xtend. warranty but I was wondering if anyone else has had same experience or ideas on cause.

Info: 2007 1600, debaffled exhaust but no other air/exhaust mods. Been running 91 oct since I bout it (3000 mi ago) and it now has 19000.

thanks for the help.