I just got done replacing the cb drive gear key ( made one myself to make sure it's real tight), because the replacement I got from yamaha seemed to have the same amount of play as the one I took out. I still have the same noise. This time while it was running, I put a mechanics stethoscope on it. I heard these sounds coming from these specific places on the crankcase side moving from the head down it gets louder and louder: Head -- sounded normal Cylinder -- more noise than the head Kick starter shaft area -- about the same as cylinder Clutch Cover -- a little more noise than cylinder Below kick shaft area close to bottom -- quite a bit of noise Below water pump -also- down by oil pump drive -- the loudest noise I still wonder if it could be excessive play in some of the drive gears behind the clutch basket ( not the clutch basket gears). These gears seem to have a lot of play on their shafts when I inspected them. Also I wonder if anyone has had issues with the oil pump area. When I spun the oil pump drive gear by hand it did not have any rough spots I could notice like a bad bearing would. Any suggestions would be extremely helpful at this point, I am at a total loss.