I don´t know that much about how bike engines work. But, if they are anything like some cars, it´s possible that your oil filter could be severly clogged, or the wrong filter, and causing a reverse vacuum flow which will blow it back out the only place there is no resistance. I had that problem on a Honda CB 500 at one time also. Blowing out that much oil though, i´m not so sure about that thought.