When i got er warmed up and just idling, either in neutral or in first with the clutch in, i get a light knocking of metal, about 3 knocks the same same harmonics as the engine sound and it goes away until a few minutes and then i hear it again, about 3 light knocks. Was wondering if it could be the valves knocking, and if so, then why only randomly?
Common on GS's, check this link
http://gstwins.com/forum/viewtopic.php?t=9811&highlight=gs500f+owners
Someone more technically savvy than I can step in to correct me, but I believe it's cam shaft play. Many of us have it, and many of have been told it's normal and harmless.
The bottom line is that it supposedly does not harm anything. Some of the higher-mileage GS'ers have said that they've had the noise for tens of thousands of miles with no problem.