On this 1976 CB500T both coils' black/white wires were found joined to a small box with a red wire and a green wire. The bike later ran on the kickstarter. That box was not confirmed as the repair.
This 1976 CB500T has two condenser cans and bullet connectors. The first replacement had a green wire and a two-prong fork, so it never met the harness. Bolting a new can down did not restore the dead plug wire.
After the throttle cable was fixed, this 1976 CB500T idled, then died with the enrichener off or from about 1,000 rpm. That is a lean slow circuit, not the cable again.
Each CB500T carb has a fuel inlet and an overflow. The two petcock spigots feed the two carbs separately. There is no crossover hose between the bowls.