I have a 2002 660 grizzly I bought about 4 years ago. Last fall I loaned it out and it came back broke and I've just now had time to pull the motor on it. It sucks because I didn't experience what happened first hand but this is what I was told. It clatter for a couple seconds them cleared up but afterwards it was shooting oil out the exhaust and out of the motor somewhere, my best guess because there aren't any cracks or holes is out of the exhaust port. She said it would still start and run but would use all the oil in 20 minutes. My best guess is the piston broke and is allowing a lot of oil past it but maybe there's more to it. Anyone have any experience with a problem like this?