I finally found the cause

[Rich82GS750TZ]

The line coming out of nipple on the front carb body # 2 that had a bolt stuck in the other end is supposed to connect to the smaller of the two nipples coming out of the petcock, if your bike has the original vacuum type petcock. The only reason this line should be blocked is if you are running a non vacuum type Pingel tap.

[Hihowyaderrin]

Where might the two in the middle “in between” section go? Would that be capped as well or just routed to an empty space just to exist?

[Rich82GS750TZ]

The two coming out the bottom in your pic are likely bowl vents that should be routed over the airbox and left open to still air. Not 100% as I’ve never had a twin.

BTW, your fuel filter, which your bike didn’t come with, looks awful. Are you sure it’s flowing fuel properly?

You really ought to start your own thread in this same carb sub-forum. Be sure to list your bike year and model in the thread title. Your issue, and any possible solutions to your issues will get lost in this thread which has very little to do with your bike, since you seem to have ruled out valve adjustment.

Also highly recommend creating a signature with your bike year and model in it (at the very least).