Carb Butterfly Valve Baseline Settings?

[RVFHooligan]

Since I have been checking everything any anything lately, I was thinking about what the baseline butterfly settings on the carbs should be. In other words with carbs off the bike, and with the idle adjuster screw backed all the way off the carb throttle cam so it's not making contact at all, EXACTLY how far open are the butterfly valves at this point? I know they are not fully closed, they are slightly cracked open. But how far open? I want to know exactly where to start before I begin carb synchronization AGAIN with the digital carb tuner. I am thinking that there is a certain amount of opening that corresponds exactly with the baseline pilot screw settings and 1300 recommended idle engine speed. The fuel that is drawn from the float bowl through the idle jet pre-mixes with air from the idle jet air passage and this is mixed with the air that slips by the butterfly valve in the main airflow through the venturi. Wouldn't it seem to make sense that if the butterflys were closed more than they should be at idle (throttle in closed position) that less air would pass through and result in a richer idle mixture? And conversely if the butterflys were open more than they should be at idle that more air would pass through and result in a leaner mixture? I know the final position of the carb synch screws will be determined during balancing of the carbs with the engine running, which measures and balances the vacuum produced by each cylinder. Others on the forum have talked about using a small piece of wire or small drill bit, light source behind the butterflys, and even a feeler guage to visually pre-balance the carbs. But again, how much? And when you are doing this, do you have the idle screw backed all the way off? I also remember reading that once the idle adjuster screw makes contact, go 1.5 turns more as a base idle setting to start with, but this again would be determined by where the butterflies were to start with. Since I have fiddled with the carbs so much I want to make sure I am starting off with all the base setting before I hook up the carb tuner. Haynes manual doesn't help here. Thanks in advance.

[Cammo]

Doing the manual balance method is a good starting point. You need to have the idle adjustor wound all the way in to start with so that you can get something between the gap at the butterfly, it's only a very small gap even on idle wound in full.

Select something small that will fit in this gap using the reference carb (haynes) to start with. Then balance the others using this same piece of metal/other in the order as per haynes. This manual balance will be pretty close to being spot on if done properly.

I would set the all carb settings back to standard also (except for main jets if changed) and go from there.

Fit the carbs back on and, fire it up and set the idle.