I put a new pipe on my bike and now I am running rich and backfiring alot. The backfiring happens when I let off the throttle and decelerate. It is a fast popping and not a loud bang. Should I rejet my carb or do I need to adjust something else? Any help would be appreciated. 

Backfiring can be caused by a leaking gasket at the head letting air into the exhaust, not sure how you added a pipe and ended up rich, it should have been the opposite 

I suspect your new pipe.If u can try reinstalling the old & see what happens.If it's the pipe your going to rejet or keep the old pipe.
I agree with Suzuki Stevo...seems strange to change the pipe(to a less restrictive i assume) and the mixture richens.
Is your air filtration system stock?

You're likely running lean if the only thing you did was put on a pipe and before that you were perfect.
BTW popping on decal is not an issue, if that is the only thing that is indicating lean.
How is it @ steady throttle. Try 1/8, 1/4, 1/2, 3/4 throttle and see if you get a lean surge.
Also plug pull @ those same throttle settings. White/ash/light grey is lean, brown, to black is fine, black to soppy wet = rich.
Cool.
Buddha.

Your header gaskets arent sealing at the cylinders. Pop the bolts out and check them along with the seal at the header and the slip on.

Are you sure it isn't normal exhaust noise?  I put on a slip on exhaust and the exhaust is louder but it also makes burbling low popping sounds when I let off the throttle.

My bike has backfired twice.  Both times were with the stock exhaust and both times they sounded like gun shots.  Bang!

Can you provide and audio recording?

Sorry about the late reply. I've finally had some time to work on my bike so I was taking the spark plugs out to see what color they were. I found out that I could easily turn them by hand. I checked them and screwed them in tight like they should be. Throttle response is better now that I'm not losing compression They were a little white though but it also may be from the bike pulling to much air. I cleaned them and put them so now after a day of riding I'll take it from there.