OK then, how i worked it out
(1) You can see the pilot air screws sticking downwards outside the float bowl
(2) you can see the carb top has a screw at the end
(3) Screw in main jet and push in pilot jet
Now all those also come on the 750 F2; F3 and Auto BUT
(4) No accelerator pump on No2 carb.
Those carbs are the ones with least detail available in any manual, the ONLY place i have found info is in the Genuine Honda Supplement for the 77/78 CB500/550 K3 and that is sparce with bad pictures