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They are attached to the block right next to the intake manifold on each cylinder. I drew diagram to try to help clarify their location. A couple of them are covered with a rubber nipple. There is a pin-sized hole on the inside of the manifold where they connect.

Are these for testing purposes? Do they absolutely need to be covered up with those OEM nipples or are those rubber nipples just there for protection?

Thanks!


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Those are to hook up a set of vacuum gauges. You absolutely have to have them covered. Your bike will not run properly without them.
Cylinder #1 has a screw with a washer. 2,3 and 4 have the boots.

 

Thank you. I'm trying to check for vacuum leaks, would that cause one? Also, do you know the name of the part(s) I would need to rectify this? I've scoured the manual (Haynes, unfortunately) and can't find anything labeling it.

 

Not having them sure will cause a vacuum leak. The bike will not run right without them. Also, I don't think the ones that are on there will work properly.
If you look at a microfiche of the cylinder head, look at items; 7, 8, 16, 23 and 19 it will show you what you need for all 4 cylinders.