1982 kz650 petcock vacuum line

I have a 1982 kz650 that was left to me and I pieced together with what was given. The fuel petcock has a vacuum port and the carbs ( pics coming) have vacuum ports behind each carb which were capped. I have been running it on the pri setting as my on and run as my off, for if there is no vacuum there is no flow. Is this ok? And is there somewhere where the vacuum line should be ran? I have ran it to the first carbs from the left vacuum port and seemed to run a lot worse than leaving them all capped. Advice sorry I've been looking but haven't found a solid answer

The petcock should be hooked up to any of the carburetor vacuum ports. it doesn't matter which one but the factory usually hooked them up to carb #2.

If it's running worse with the vacuum line connected, it may be that the diaphragm is defective & needs to be replaced.

ogowen wrote: I have been running it on the pri setting as my on and run as my off, for if there is no vacuum there is no flow. Is this ok?

It would probably be better to run with the vacuum lines hooked up so you could just leave it in the Run position all the time and not need to worry about switching it on before a ride and off after a ride. But what you are doing is effectively using it as a non-vacuum petcock. It will function fine like that.

Possibly a cracked or otherwise leaking vacuum hose.

If condition of the vacuum hose is suspect, would fit a brand new vacuum hose.

Good Fortune!

Earlier kz650s with VM slide carbs had their vacuum line connected to carb #2.
The four rubber caps on the manifolds are for synchronizing the carbs, but one can be used as a vacuum connection if needed.
The '82 kz650 has BS32 carbs (CV type) I believe, and am not sure where the vacuum connection is.


VM slide caebs:

BS carbs: