[Shimpdogg]

Hello. I just got this bike and let's say that I'm finding out all its skeletons in the closet.
Cranks over no start.
Fuel petcock works. But no vacuum line just one port.- fuel
PO claimed his guy went through all the carbs ( maybe)
I found a capped line on the second carb from the right which i assume is a vacuum line? If so where does this go?

I do see a line from the top of the engine to the airbox and I think it might be related.
Thanks for any assistance.

 

[DannoXYZ]

First priority should be to find official Honda workshop manual for that bike.

 

[pdcomm]

Exactly which bike is that ?

Answer : 1982 CB650SC A .

 

[ExTex]

I would guess that the capped port on the carb is for the vacuum to be used on the original petcock.

Looks like your bike is a 1982 Nighthawk 650 ?

 

[pdcomm]

That brass tube pictured is an adapter for vacuum gauges used to balance the carb bank .
The vacuum line for the OEM petcock comes from the forward mount of carb #2 ( 2nd from the left ) .