I am new to this forum and I need help.I got this 300ex on a trade for some work that I did for someone. About 2 days after I got it I found out that it is smoking. It is not smoking out of the exhaust, there is some kind of a vent hose on the back side of the engine and it is smoking out of it. I don't know much about these bikes. What could it be and what do I check, or do I just need to rebuild? Could it be the rings, or is it the top end? Need suggestions.