Whilst doing some ignition misfire trouble-tracing on my B Meteor I noticed that the bakelite end cap on the dynamo was wobbly. See video. I couldn't see any obvious threaded fasteners holding it in place and I didn't want to start tugging/twisting things. Is this just a loose end cap or is there a bigger problem? If it's just a loose end cap, how does one tighten it? Since I have a modern BTH "magneto" on this bike, I didn't think the dynamo issue was related to the misfire.