Just got a 04 150 4 stroke for 750 bucks. Excellent condidtion, but smokes a lot. Freaked the other owner out and he sold it cheap. I have worked on 2 and 4 strokes before so I did not think it was a big deal. Maybe some piston rings, valves, or a seal.. but I am coming here for more info. The bike still rides strong (compression is good), but smokes like crazy out the exhaust. I checked the valves and they are super tight, no clearance! Could that be causing the smoking? Now the real Newb question... (kind of embarrasing). I removed the engine cover for the rotor and it was full of oil, to my surprise!! I never worked on a 4 stroke that had oil flow to both sides of the engine. Is this right? Also are there any seals that might be a problem with the oil going up the timing chain and being blown out the exhaust? I put some oil in it for a test drive and it burns it really fast, but the bike runs good. The oil has to be getting sucked out of the crank and blown out the exhaust somehow. Any help or info would really be appreciated.