Topic: 1977 keihin carbs for cb750. Pilot screw adjusts air or fuel?

[547]

Can anyone explain to me what the pilot screw on the '77 keihin carbs (accelerator pump equipped) adjusts? air or fuel? and also if I am
adjusting the right screws. they or on the air box side or engine side?
thank
j-

[eldar]

They adjust fuel. In is lean. Out is rich.

[750Caferider]

Reference for the idle adjustment is turned all the way in then turn out 1.5 times.  Use the notch in the middle of the knob to clock it out.  Mine sets at 1.75 turns out.

[750Caferider]

The air fuel ratio adjustment is on the bottom of the carbs towards the engine.  It will be brass and can be adjusted with a small stubby flat bit(regular) screwdriver.  Regular stubby won't due on the left side.  Not sure on the Reference setting on these though.  I'm currently trying to adjust mine!  Any Help? Hondaman? TwoTired?

[TwoTired]

The PD carbs adjust the total delivery of air frothed fuel from the pilot jet.  As such they behave as though they are adjusting the fuel quantity.  Turn in to make leaner, out to make richer.  NEVER seat the screw more than just lightly seated.  The needle tip is quite narrow and they have been known the break tip off and plug the exit hole.  Then no more pilot fuel delivery.

The Honda manual for the K7 says the setting is normally around 1 1/2 turns out.  Stock bike of course, with stock air filter and exhaust.
The enrichment range is quite limited.  Really only effecting idle speeds.  The EPA didn't want owners changing the setting so much that idling pollution increased.