My brother just bought an 03 banshee and put fmf pipes with the silencers on it. We noticed an excessive amount of oil dripping out the back end of the silencers. this isn't supposed to happen is it?

 

What is he ratio is he mixing at?

No, you should not have oil dripping out of the silencer. I get a little ring around the end of the silencer, but no drips, I also get a bit of oil around the right side where the pipe meets the stingers.

Bat

 

The Jetting is WAY too rich!!

As Bat said... shouldn't be any oil dripping... a little residue is fine.
Either fuel/oil ratio is really messed up or he needs to adjust the jetting.

 

Did you rejet after the pipes?

Chances are you are too lean. Does it smoke excessively? If so, that is probably what it is. Two-strokes actually smoke more when lean.