I have a 2003 YZF450 that I bought recently with low hours on it. My second ride on it and I appear to have blown 3rd gear. I landed from a jump and it made a horrible clanking sound. I thought the motor blew up. I pulled in the clutch and killed the engine. When I started it back up it ran fine and went thru the gears but now everytime I let off the gas in 3rd it makes a grinding noise and vibrates. Anyone else have a similar problem? How big of a hassle is it to split the cases on one of these? Thanks in advance.