I have a Strange Quill Removal Question.

By quill I mean the handlebar stem. Please look at the picture.

I have an older bike (1986) that has been retrofitted with a Tranz X "Zanzi" stem installed on a sleeved adapter.

I expected to see a bolt head of some sort on TOP of the adapter that would allow the adapter to be removed, but the cover plate on top of the adapter shows just a smooth, blank surface.

How does this come apart ? All advice or suggestions appreciated.

Binky