I use to have 2000 600 Grizzly. Do you know where its coming in at??? when i had mine i opened up the box one time and it had oil in the bottom. it was actually oil from the filter, the filter oil got hot and leak down. the place that oiled my filter put way too much oil on it. Have you thought about that??
as bluerider mentioned, it should be a simple fix or clean up rather. a good foam filter oil is called for but not in excess. Hows your bike running, any smoke out the pipe?
It could be a worn set of rings.Possibly a groove in the cylinder allowing compression to get past the rings, and into the crankcase, and then looking for an exit, the air filter is next in line.Just a hunch, has the thing been flipped over?
It's running fine now, I just got it. Noticed it was way over full on oil, changed oil, runs like a dream. just has 3000 miles on it, but a diesel mechanic owned it, he just rebuilt everything in it, don't know why so soon, but it has alot of power..