Why do the '83 carbs recirculate fuel back to the fuel tank?
Wish I could answer more of your 83 carb questions, but they're a bit different than the 82s & I've never had a good look at them. As for the fuel recirculating, this prevents the fuel in the float bowls from overheating & boiling. The 82s have this problem, making them difficult to start when hot.
H2O
it's just a different mouse trap. Just a different way of excess pressure from the OEM pump to go somewhere. Put an electric pump on and you can forget everything. Leave it on prime and ride....