I was riding my 06 WR 450 up a stream at the end of the riding day where the water level was only up to the brake rotor at the deepest point. When I stopped at the end I shut off the bike for a few minutes to talk with my buddies, and when I started it up again RIGHT AFTER the starter engaged something made a whining sound for a second and went away after it was running. It only happened when starting, and even when I kick started it the same whine happened. After I got home and took it off the trailer I started it and the sound wasn't there. I haven't had the chance to ride it again or change the oil for that matter. Anyone have similar experiences???