My bike has 7700 miles and started making a noise that appears to be coming from the rear drive. I first notice it above 20 mph, in all gears, accelerating, holding constant, decelerating and coasting (clutch in). Sound is like a small pebble bouncing around inside the case. I need to do more diagnostics, but my first inclination is a bearing failure. A quick google reveals a common bearing failure in the gear case. Some quick questions: does anyone have access to the actual bearing numbers used (some prices look hefty on part sites); is Clymers or Haynes a better repair manual; are special tools required or can the average bear tackle the job? I greased all the splines at 7000 miles and the gear case is full of oil. I plan to get a stethoscope and run the bike on my lift to see if I can locate the source of the noise. thanks.