Those carb hoses?

[rickt]

Trying to get everything ready to finish the '78 GS750 restoration in the Spring. I know I need to replace all the rubber hoses, but I'm a bit confused about the connections. The attached pic shows the blue connector that is the fuel in from the tank petcock and the green vents on each of the four float bowls. The three red connections are my problem - I assume one (or more) of these must run to the vacuum connector on the fuel petcock?

Can someone please clarify!

[Nessism]

Hard to tell from the photos but the outer carbs have vents and the inner has a vacuum port. The vents interconnect between carbs so check the passages.

[Sandy]

On the GS1000 VM carbs the vacuum is on the #3 carb. Your 750 should be the same. If you put a piece of hose on it to blow through and compare it to the others you'll see the difference.

[Steve]

The center red connector is your vacuum port that goes to the petcock.

The other two are the vent lines that go back over the airbox and just lay there. They are not connected to anything else.

.

[Nessism]

Photo below is from my old 550's carbs. Vents are the outer tubes. Large tube in center is for fuel and smaller hose is vacuum.