If memory serves me right, idle speed is to be 850-1150 rpm. The tack on a Speedy doesn't even register below 1100, so I turn it up just until the tack needle starts to bounce, then back off a slight hair. If I try to lower the idle to less than say, 1000, it sometimes stalls when cold or even too hot...or even taking off from a stop. Also, if you ride in various elevations, the idle needs minor adjusting to keep it right. That is most likely why the idle screw is so easily accessible.
I have also noticed that it runs best at idle at 2 1/4 turns out from the stop on the mixture screws, and then a + or - 1/4 turn for smooth quick-snaps of the throttle twist. I have also figured out to stick with the stock 42 pilot jets with an uncut or non-removed airbox. This eliminated most deceleration pops (hot, unburnt fuel igniting when reaching the outside air at tip of the tailpipe = rich condition) It also can't hurt to make sure the carbs are balanced (synchronized) at around 2500rpm.
You really don't need to remove the carbs to remove jets. Just drain the bowls and unscrew them. I put in allen/hex screws to make this a snap. A flexible precision screwdriver really makes it easy... for bowl removal and of the pilot jets too.
like this one I used the largest flat bit for the pilot jet with the slight help of a small socket, 3/16", it think it was.
