THE REAR WHEEL OF THE MOTORCYCLE UNEXPECTEDLY LOCKED UP WHILE DRIVING ON A CITY STREET. I LOST CONTROL OF THE MOTORCYCLE AND HIT THE CURB. IF THIS WOULD HAVE HAPPENED ON A BUSY INTERSTATE, I COULD HAVE BEEN KILLED. THE REASON THE WHEEL LOCKED UP WAS BECAUSE THE MANUFACTURER USED THE WRONG BEARING ON THE DIFFERENTIAL PINION GEAR. THE BEARING WAS NOT DESIGNED TO HANDLE THE THRUST IN THIS TYPE OF APPLICATION. WHEN I PURCHASED THE REPLACEMENT BEARING FROM THE YAMAHA DEALER, IT WAS A BEARING DESIGNED TO HANDLE THE THRUST OF THE PINION GEAR. YAMAHA NEEDS TO INITIATE A RECALL FOR THIS PROBLEM IMMEDIATELY BEFORE SOMEONE DOES GET KILLED!!