1979 GS750 carb vacuum ports identification

[Runningdog]

Continuing with the assembly of my latest basket case, I note that there are three vacuum ports on the carbs: #2, #3, and Groups Blogs has a brass port on it, (with a cap on it), but the other two had 5mm bolts siliconed in. I believe that the #3 is where the petcock vacuum goes? What is supposed to be on the other two? Where can I get new brass ports?

I miss being able to see photographs of just this type of thing on Bikecliffs Website, but too many included photo-hosting sites that no longer work.

[Rich82GS750TZ]

This is the image you are looking for. # 3 is the only vacuum port to petcock. The other 2, on carbs 2 and 4 are float bowl vents. These should have hoses attached and should usually be routed up over the air plenum and terminate in still air, typically somewhere above the air box.

I’m sure the brass nipples are not easily replaced. But if anyone has successfully done this, I’d put my money on either Nessism or Chuck Hahn

[Runningdog]

Thanks, Mr. TZ......that's what I thought.

I have seen threaded ports on Z1 and other places, not difficult to tap some threads into the carbs.