Hi Puffs the weird description is in the official MZ parts book. It is only when I saw the term "cylinder head screws" on a diagram that was not engine related the "penny dropped" and I realised what was being said. In fact there is nothing wrong with the term/description*. It is accurate but simply conflicts with an engine part name. Here is one such page...Part numbers 3 & 4: (click on image to enlarge)
Now maybe you can see why I made the thread?....Although I was humorously mocking myself, there was a chance that it would also help others who might have been baffled by the odd description
* I suppose it would be more correct to call them cylinder head
ED screws
However I have never worked out what EM, BM, CM etc. means...Perhaps Guesi knows?
Les