I have an 07 with 9000 miles that has recently started the cam knock. The valves were just adjusted. I used 15/40 on the oil change as well. It didnt help any with the knock. I ordered new wavewashers its 5 or 6 dollars for both.Thew new ones are alot stiffer than the old ones.You just have to remove the tensioner and pull one cap at a time. My chain slipped and all the timing guides on the net are for the older two pickup models and mine has the single pickup.Can someone let me know how to line up the marks so I can get this thing running and let everyone know if the new washers help.Thanx for any help

I believe old and new the timing is the same, they use the same cam sprokets and cam chain, so the marks sould all be right where they would be on the old one.
Cool.
Buddha.

Its the pickup on the side case thats different. The newer ones only have one pickup and all the directions are for the older bikes with two.

Well you can put the cyl @ tdc using a dowel.
The ignition rotor is pretty good way though, but what you need to do is find the TDC for each cyl.
Cool.
Buddha.

Go to 09 Service Manual for GS500F and download and open. 

http://www.partshark.com/custompage3.asp?pg=suzuki

Page 378 under 03 updates shows position of rotor for right cyl at TDC for adjusting valves and for camshaft assembly.

Thanx guys I got it,I will let you know if the washers help any.

My GS used to get cam knock only on hot days when the PO had used 20w-40w oil in it. Only happened on hot days when I pulled up. After the oil was changed to the specified 10w-40w I haven't heard it.