1976 kawasaki kz750 carb

i have taken my carbs apart for thorough cleaning and had vacuum leak on the rod with the butterflies does anyone know where or what size of screw holds the butterfly on?

Two screws on each butterfly, little tiny things that fit through hole in the butterfly and screw into the shaft.

If your throttle shaft bores are worn, a good machinist can bore out the throttle shaft bore and make bushing to press back in. Common fix on Kohler motors.

Or you can hunt around for a good set of used carbs.