I have a 1992 Yamaha Banshee and it is spitting oil out or the vent tube coming from the back of the crank case... Do Yall have any idea on what my problem is?? It only has about 18 hours on it.. My oil Level is fine and I have all the power I should.. Have any of you ever heard of this on a two stroke of four stroke either one?? Please Help. . . .

 

Oh and it doesnt do it all the time. Only once i run it for fifteen to thirty minutes or so...

 

Your tranny is seperate from your engine (unlike all the 4-strokes except the Honda 450R), so I would suspect a seal or gasget is going somewhere and passing combustion gasses into the crank case. If so, your tranny oil won't hold up very well, so I would change it often until you sort this out.