Not one to do a whole lot of my own maintenance, I was motivated while going through all your "how to" threads, which you have do a super job on!
Today I tackled the valve adjustment and throttle body adjustment on my 07 GS. My bike has been idling rough, and backfiring more than I thought it should. The valve job went smoothly, and everything was pretty good except I had a tight exhaust valve on the right side. Easily taken care of with your directions, and I got them all adjusted in less than a hour. Not bad for a rookie.
Ok, on to the throttle body adjustment. I guess I was one of the unlucky ones. My idle on the Twinmax bounced, with a 2 as the center. You say you have never seen that, but I sure did. Lucky me.....
Anyways, I ran the RPM's up, at 2K and 4K the needle was dead center, or too close to worry about. So then I started to look at the idle you say there is no adjustment for. I crawled below and watched the bodies move (with the bike off) as my wife ran the throttle, and I could see a stopper screw where the spring loaded plates stop against.
So looking at the top of the bodies, I saw a rubber cap covering a 10mm screw. By backing out the left throttle body screw, I was able to bring my Twinmax needle to center, which started out way to the right. I gotta believe that is probably the way to adjust the idle, you can take a look and verify if it looks right to you. My idle immediately smoothened out.
Here's a picture of the screw, it has some blue silicone looking goober on it that held the rubber cap on, or maybe it is blue locktite. In either event, it was easy to adjust.
I just took the bike out and it runs smoother than ever. And it quit shaking at idle, which is why I was wanting to do this work in the first place.
I'm pumped! Thanks for all the good info you provide, it's easy to follow and understand.
I'm off for an afternoon ride!