What Goes on Here? - Sorted, I think?

[Efes123]

OK. I seem to have aome play in the yoke, and I feel as though I'm missing a part. The yoke looks like this;

https://www.ebay.co.uk/itm/SUZUKI-GS125-1988-BOTTOM-YOKE-BREAKING-BIKE-4-SPARES-/281002135833?pt=UK_Motorcycle_Parts&hash=item416d085119

All I have is a rubber cap that sits on the top, under the main screw. Looking at the top end of the yoke, there are 4 slots cut out, you can just see them at the bottom of the picture. What goes here? It looks as though something should slot into it, not just have a rubber cap, tope of yoke, then the screw

EDIT:
Looks like it should have another one, and they're called top lock nuts
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