Air box vacuum switch hole

Restoring a 82 KZ750E3 Canadian model. There is no vacuum switch on the air box since it does now the air injection system like the US model. When I got the bike the hole in the air box where the vacuum switch would go was not plugged.

I am assuming that this should be plugged as it would introduce unfiltered air. Am I correct in this assumption.

Also progress of my frame up restoration. Almost done

I would certainly think so.

That is what I figured also. I have gone ahead and plugged it up. Strange it was not plugged off at the factory. Perhaps not the original air box to the bike??

Did you check the plumbing inside the airbox? I'm wondering if Kawasaki made the provisions there. ???
The Canadian airbox assy has a different part number, but from the diagrams it's not readily apparent what might be different as the drawing doesn't show anything.

I did. The hole goes right into the air box. No plug at all. Perhaps was there at one time? Connects with the breather hose. Plugging the hole on the outside just leaves the breather drawing vacuum into the box as it should.

Thanks. I forget exactly, but there is some tubing inside my airbox connecting the breather & clean air system. I was thinking maybe the Canadian model differed in that respect, so maybe something is missing. just a wild guess. My airbox should be pretty much the same as yours as it's embossed w KZ750E/H.