I have spent a long time looking around for an answer to this but no luck.

I just took out my air box and replaced with a uni filter. It looks pretty sweet and i'm stooked to try it.

Just wondering though, there was a tub that plugged into the side of the air box (which it then runs into a small box and then into the ignition case area. now that i have a foam air filter on i don't have anywhere to plug this tube and i dont know what it does. Is it the "crankcase vent" and i i should buy an external filter for it like this http://xr50.com/ap8mmcrvefi.html ? If so, is it possible to run without a filter or will dirt be sucked in or gas and junk leak out or what?

Im amazingly confused here and want to start this bike up. Thanks for your help!

You hit it on the nose. It is the crank case vent. You can go down to Auto Zone and get a small filter that will plug into that hose. I know some people that never put anything on it, but I think that is dangerous.