I set the float bowl height to 17mm per the shop manual and visually bench synced the carbs. ......
now, after explaining the pilot air circuit, and it's GREAT importance to starting the bike, and supplying fuel for IDLE, and just above...
HOW did you (explain the method) accomplish your "bench synch"?
When I instruct this process, I direct people to adjust the "idle" knob, to a point where the fixed stop on the carb casting is reached, then, I add 1 turn on the knob, just to "raise it off the positive stop".. then I proceed to adjust the individual carbs, the actual "adjusting screws", to move the throttle plates to a point where each and every carb has the "leading edge" of the throttle plate "covering" 1/2 of the forward hole in the throat... when observed, the "reflection" of the hole, on the throttle plate's bottom edge, should combine with the hole, and make a "perfect circle" in it's reflection, if it's less than that,
the bike will not start, (so erring on the heavy side, and if the reflection is actually a "figure 8",
it will still start... and backing off
later on the knob will bring it back to the correct point) but the "circle" is what you shoot for..and
all of the carbs must be equal... and this is all done as I noted before, after installing the pilot airscrews, fully, and backing them off 2 full turns.
if all that is followed, sticking a "synch gage" on the carbs is almost never needed, because they will be soooooo close just sticking the screwdriver on/against the adjusting screw will make it change...