I'm going to check the valves on my GS after work today (she's been sitting at my grandparent's house since Sunday - they have a nice garage) and I was wondering if there are any specific things I should be aware of.

Before anyone screams "SEARCH!" I've already read Egaeus' and Mandres' threads (what not to do, and crazy valve clearances, respectively) and have downloaded and watched Kerry's video.  I don't have any reason to believe that there is anything wrong with my clearances, I just want to check since I just got the bike a little while ago and have no way of knowing what the previous owners did.  She's got a little over 6400 miles on her, and I know that valves should be checked every 4k, but again, I don't know if it's ever been checked. 

Also, this may be a dumb question, but do the jets have their numbers stamped on them or are they marked in any way?  I want to pull apart the carbs to see what the first owner did with the jets.  I was told by the previous owner that the other guy rejetted, but I did not get any specifics.  Any hints on that would be appreciated as well.

Thanks in advance!

You should be fine with Kerry's video.   

Yes, the jets will be stamped with their size.  There's a jetting matrix that will help you determine a baseline for your setup.

I'd offer further advice, but it sounds like you have an F-model.  I'm unfamiliar with the carbs on the F.

He has a 2000.  Here's the FAQ on the jetting: http://gstwins.com/gsboard/index.php?topic=12929.msg108864#msg108864

Thanks a lot, I'll report what I find out tomorrow (or later tonight if I feel like dealing with the dial-up)

Well, even though my GS runs great, I found out that the right exhaust valve has a clearance of 0.04mm, and the other three have less than 0.038mm.  I'm not too worried about it since I can spin the buckets pretty easily on all three of the tighter valves, so I know there is a little bit of clearance.  I'm going today to buy some smaller feeler gauges so I can get a better idea of what's going on. 

One snag, though: when I disconnected the fuel lines from the tank, I found that the hose toward the front of the bike had hardened under the clip.  Upon removing it, chunks crumbled off the end, so I'm going to replace those two fuel lines.  (If I replace one, I might as well do both.)  One thing I'm wondering: do I need to take the plastic sleeves off the existing hoses and slide the new hoses through those, or am I safe without them?  It's no big deal to do it, I was just looking for a second opinion.

I also found out that the drain hose from my tank is missing.  Anyone think this would be a problem?  I can just pick up a little extra fuel line and install it there if I need to.

Thanks again everyone.

I'd replace the drain line. If you don't and have a spill when filling her up it will go right on the hot engine.

Thanks Markus, that's what I figured.  I didn't think the engine would be hot enough to really cause a problem, but I don't exactly want gas all over it either.

It probably wouldn't spontaneously ignite (since it's on the cool side anyway). Still it's a heck of a lot more dangerous there than on the tarmac.