Popping and backfiring usually mean you're running a bit lean, which is typical for aftermarket pipes. Check some of your plugs, if they're an ashy white you need to richen up your carbs 1 maybe 2 steps. If they're nice brown, you're perfect and black, but not wet you're ok, but a bit rich. But sounds like a lean condition to me.

 

+1 phoenix239

And are you running the D&d with a stock filter setup or high-flow?

 

While Vortex make some really nice products ( run their rear sets) their rear sprockets wear quickly. Try AFAM for the rear. Its hard anodized aluminium. They last much longer and are very light.

 

From Rouge Racing. Dan the man Kyle and Mike Wheeler.
http://www.rogueracing.org/gearing.htm

 

Thanks for the link Sarge22. Here is an awesome gear ratio calculator that someone on another site posted for me. Maybe it will help out someone on here too!

http://www.gearingcommander.com/