I had a problem with the idle on my 2004 1150gsa. Sitting in traffic, out of town, engine got really hot (almost to redline) and the idle was just high and wouldn't drop. Ended up screwing in the Big Brass Screws until it dropped down an acceptable amount--nothing else to do while sitting in traffic. That might be what Steptoe was talking about. The guy's a genius. Figure out what he's saying and do whatever he says, first.
Anyway, I stopped at a hardware store, got about 10 or 15 feet of small, clear tubing and made a synchronizer with some zip ties and a little 30 wt. oil that I carry with me, and a straight-ish tree branch I found. Worked fine. Suck the oil into the tube as if it were a straw. Pouring it in won't work. A couple of feet of oil is all you need. Fold tube in half (equal length each side) without kinking the bend, and zip tie it to the branch. Yardstick or wooden dowel would work better.
Big Brass Screws adjust the balance at idle and the cables adjust the balance "at speed." Set cable freeplay, and then work from one side. The Hall of Wisdom link at the bottom of the page, here, will tell you all you need to know.
Dan Cata (I think that's the guy's name) makes rebuild kits for the throttle bodies. You can find his link around here somewhere. I haven't gotten one, yet, but I need to. It sounds like you might need to get one, too.