If all 4 carbs have adjuster screws you can decide which carb to use as a reference when syncing.
Important to have idle screw lifting all into an OK position when all 4 are in the middle adjustment wise.
If throttles:
Make a 4-5mm drill to match one throttle, adjust the other so drill will fit in same way. From inlet side.
My stock CB750 K6 carbs have all adjusters.
I made sure during initial bench sync that all carbs were in the middle adjustment wise. So they can be adjusted in both directions.
I used no 2 as a reference. Adjusted 1,3,4.
If adjusting all, a risk that the adjuster will enter the outer end on one carb, not possible to adjust as needed.
My Mikuni TMR32 has no2 as fixed reference since that has no adjuster.
I have synced these several times due to rebuilds. Very often that 1 carb is off, the carb beside the one that make it good.
One carb can be open more than the other causing engine to rev faster.
My thoughts about it:
This make the others to slaves when higher rev make the other carbs affect the sync tool inderectly.
So find the carb that affect revs most have been the thing with my TMR flatslides syncing sessions. Adjusting the other does not help as much as it should. It take some fiddling to get the feeling for it.
Not only an even idle, slow throttle roll-on up to at least 3000rpm and still in sync until OK. Hopefully during slow roll-off too.
I use Morgan carbtune tool.
Do not forget a fan cooling engine during sync.
Lean low jets /screws will make this to a hell. Just a little wrong will affect much. Same during take offs when riding. Hysterical throttle not fun.
