I own a 95 Wolverine and, occasionally, there is a knocking noise coming from the crank case. I can feel it on the left side of the motor where the gear shift is. I changed my oil and found copper(?) shavings on my oil filter. Very fine...you couldn't feel it but you could, definitely, see that it is bronze in color. It, usually, does it when the motor is under a load like motoring through some tight woods or under full throttle. My guess is that it is the link inside of the crankcase for the front axle or maybe a clutch is coming apart. Any ideas? I want to get this repaired before I put a big bore kit in.