EddieEarly versions of this single magneto have an extra part on the end cover with the BT-H logo machined in. This made it easy to locate and secure the items/wires inside and then fit the logo item to cover the hole. The Comet version didn't have this extra part because it had to be short enough to go under the magneto cover. The dome head Allen screw at the bottom right hand of your photograph holds an earth wire and a clamp for the CDI unit. It was awkward to fit things in and keep wires clear of the rotor arm. The end cap is held on by the Allen head caps screws, one of which can be seen at the top right of your photograph.
If you are going in there I suggest you go very carefully.
(This is a bit like a UXB defuse) I have removed the two screws but the cover wont shift with normal hand pulling. As its off the racer I expect there is a contingent of congealed R pulling the other way
so questions questions
would it be OK to inset a thin blade in the fine joint twixt cap and body to ease the cap off? could a smigin of petrol round the crack hurt the contents? is the cap over a long shoulder of the body or a short one? must I take care with the strength of pull and the distance moved because wires attached to the body and cap will be under strain?