What are these clear hoses for on my 78 KZ650 B B

What are the 2 see through hoses connected to carbs 2 & 4? Do I need to block these off before doing the carb syncs just like the vacuum line to the petcock? Thanks, Dave.

Those are float bowl vent hoses. They should remain open. As I see it they allow air in and out of the bowls as fuel level goes up or down. In turn this allows for atmospheric pressure on fuel in the bowls.

and keep water out of the carburetors. : )