I know what a Main jet is when referring to carbs in the Haynes manual, but what are main or slow air bleeds or even a slow jet...the terminology is confusing

well, you got idle jets, that are open when idling. you got slow jets, that are just off idle, or may also be called idle jets(depends on carb, i guess) you got intermediate jets, between the slow jets, and the main jets.

 

the different jets, are what makes the different circuits of your carb. they all overlap eachother, as you push down on the pedal further and further.

and slow air bleed is a needle that lets in air past the throttle plate, i think its an idle mixture setting, not nessecarily an idle speed adjuster, but it effects idle speed. you set the air bleed before you set idle. afaik.