I rolled my magnum 500 this weekend and i did this before but this time a whole bunch of oil ended up in the air box. why does it do that? i cleaned out all the oil and junk. and i checked the oil level and it was good.

 

Your vent from the engine more than likely goes to your airbox. If it was upside down then oil would've went through the vent hose to the air box. Simple as that.