I have a 2004 WR450 (LOVE IT) and it is making a strange noise around the cylinder head/jug. I took it in to the dealer to have the valves checked and everything was good. The mechanic also said that he put the pistion at TDC and tried to push down on it to see if there was any play in the piston pin....none found. I drianed the oil when I got home and changed the filter.....nothing out of the ordinary in the oil/filter. Then I took off the clutch cover and found nothing wrong there either. Anybody have any suggestions. It still runs great and has plenty of power....but the slight knocking (pinging) noise is troubling. The Yamaha mechanic said that the engine was known to be "loud," but I still have questions. Thanks, T-Dawg