kz700 bogs low rpm

So I need help with my 1984 kz700.
I have a bog at low rpm...worst in ist gear when taking off.
I was adjusting the fuel screws and the outside right carb does not cause the bike to die when gurned all the way in but the other 3 do.
Actually turning the screw on that carb makes no difference at all...but the other 3 you can tell.
it has pod filters and a kerker muffler with packing.
the last owner had it rejetted by a kawasaki tech but I dont know what jetting he changed.
What would cause the bog and why would the one carb fuel screw not change the way it runs.

When a mixture screw isn't doing anything, in my experience it's time to pull the carbs, and pay particular attention to the carburetor mounts on the head, and the clamps, and see if there is a vacuum leak.

Good luck.

When I sprayed carb cleaner around the boots I didnt notice any idle change.