There are a lot of guys on here with more experience with valves, but this is mine:
My manual called for checking the valves at 15K. After joining this forum I determined,, based on what others said, that 15K was way too long to wait. I checked mine at about 6,000 miles. I believe one exhaust valve was completely out of spec (tight), the other exhaust valve was at the lower limit and both intake valves were more than halfway to the "tight" side. I'm too lazy to go get my work sheet right now.
I'd noticed one of the symptoms of the bike taking longer/being harder to start. So, at 6,000 miles, they were obviously due a check.
I don't know about the 600-mile interval. I was going to say it seemed unnecessary, but just noted BUGKLR posted that he's seen a KLR at those miles with tight valves.
I don't know if Kawasaki will do it now under your maintenance agreement or not, but if you plan on keeping your KLR for a long time and that agreement runs out, you'll have to do it again yourself or pay them to do it.
Trust me, if I can do it, anybody can. It's a simple task. Paying somebody to do it is a waste of money and it's actually very satisfying to do it yourself. When I had questions about shim dimensions, where to get them, cam chain/timing issues, I popped on here and had my answers in no time. I used a Clymer manual and overall it was sufficient, but didn't address a couple of things I needed to know during reassembly. The only special tools you need are a feeler gauge and a couple of torque wrenches as far as I can recall. The biggest PITA is getting the fairings off and back on.
Last edited by planalp; 06-13-2012 at 09:37 AM.