Carbs off my 78 KZ1000, what goes here?

The triangle shaped thing. I removed the accel pump. There is something missing. Does it need it? What is supposed to be here. What does the outlet go to that they have a rubber plug on? Do I leave the plug?

nothing.

Happy new year. The triangle, secondary accelerator pump should be blocked off with a little ball bearing and is not used. The nipple is an overflow port and since the pump is not used can be capped off. It looks incomplete but is fine as is. The square accelerator pump does not really do a lot either but you can check it by pumping the lever while on the bike with the air box and/or filters off and you will see a little gas spray come out. That is my experience with these accelerator pumps but I am sure someone more knowledgeable will chime in.

The VM24 accelerator pump on my 81 650 is similar: the triangular vacuum sensor was disabled at the factory. A K&L rebuild kit includes the sensor diaphragm & spring, but the stuff isn't needed on models such as mine in which the sensor isn't functional.

The kit also includes a ball, weight, & clip: each float bowl should have those little parts.

The #2 bowl on my bike has 2 ports. One is for the carburetor overflow & the other one is for draining the carb.

Z1Enterprises.com - Accelerator Pump Kit - KL18-2903

So the accelerator pump is not needed either?