So I dropped a valve shim down in the engine. When I looked down in there with a flash light I couldn't find it so I spun the engine a few times by hand to see if I could hear it or see it moving. Nothing. So then I took off the cam shafts for a better view and looked again. Nothing! So I just decided to fish around blind with a magnet for a while, and not surprisingly, again I got nothing. Can I just give up on looking and leave it in there (I am hoping yes, but guessing no) or do I need to take off the head and just keep digging deeper until I find it. Thanks for your help.
Drop the oil sump and have a look from the bottom. You will need a new oil sump gasket. It goes without saying, but I will say it. Remember to stuff a rag down there next time before you start replacing shims. Many of us, myself included, have done what you just did.
You probably won't see anything from the sump. There are splash guards below the crank.
If I recall correctly, there aren't any particularly large gaps around the cam chain for a shim to get through. I suspect the shim will be somewhere in the cam chain tunnel.
I would advise against leaving the shim in there. The GS engine is very tight. I could imagine all sorts of bad places it could get caught, causing all kinds of problems.
I would play with the magnet some more. I've dropped a few small items in there and was able to fish them out with pliers or magnets.
I dropped the sump and fished around from the bottom for a while. It was a tough find, but I retrieved it. Thanks everyone.