I wanted you to see the IDLE SCREW and the little throttle slide guide and the fuel tickler, push it down for a few seconds and it lets fuel in the carb for a cold start along with using the choke. I don't use it myself.( the tickler)
when you go to put the slide back into the carb make sure, I mean damn sure you put the slide in the carb matching the long slot of the slide with with the small pin in the carb (aka. the slide guide0 it is on the opposite side of the idle screw. Look it over closely work the throttle twist grip while looking into the throat of the carb(air cleaner off ) making sure the throttle slide closes all the way and opens all the way. If you don't do this step you might get a "Mr. toads wild ride' the first time you fire up your bike. YOU DO HAVE THE KILL SWITCH HOOKED UP RIGHT? Good for you now letsw continue with tearing this unpolished turd up.
I have the idle screw label inside as idle speed tit in slide body. It should be just the tip of the idle speed screw. the idle speed screw works on the short notch of the throttle slide holding the slide open just enough for the engine to idle when you get the idle speed screw adjusted to your liking, the slides short notch is angled for the idle speed rounded off end to sit against as you turn in the idle speed the rounded end pushes against the angled notch making the slide open up a little for the proper idle. How fast it idles depends on you or what you like for an idle speed. If your running lights then you might want a faster idle if it dies when your light are turned on .