congrats on the bike - idle control should be a round silver knob just peaking out on the left side (as you're sitting on the bike) from under the frame spar, a few inches behind the choke lever and right by the radiator overflow plastic container on a stock set-up. Gawd it's nice to be able to answer somebody's question for a change! Hey, it's a start.
_________________
-Jim
'93 MC21