Talk Morgan Forums Thread Like Summary - M3W License / Number Plate Connection

My "Number Plate Mounting Panel" rattles because its not connected to the chassis on one side. According to the Parts Book, the connector is a countersunk M6 x 25mm flat head socket screw. One the one side, the screw is tight and holds in place. On the other side, the screw does not turn, but the plate moves freely in and out of the end of the chassis. Does anyone know how this is fastened inside the chassis? Is there some sort of threaded insert? I don't see any references in the Parts Book. I doubt the chassis tube itself is threaded.
Any photos would be appreciated. Thanks in advance.

I believe that there is a threaded insert. I have always had problems with the screws working out and have reverted to using Loktite there and on so many other points of this car. It is, after all, literally trying to shake itself apart!

A rivnut - maybe just buy a kit of them from Amazon et al?. Just changed my socket screw to a bulb head M6x25 to hold a badge bar, and added a locking washer.

I would use proper penetrating oil not WD40, if the issue is purely that screws will not unscrew, and left for 24 hours. Then use the correct 4mm hex (allen) socket on screws. Failing that drilling off screw heads then drilling out remaining thread to allow re-tap may be only course of action.

It appears though that one of the tapped welded in chassis plugs has loosened so you may need to get that re-welded in place.

The plate mounting panel is heavy and the vibrations do, in time, pull the rivnuts out. A good solution is to replace the rivnuts, and replace the steel panel with a much lighter aluminum one.
Another approach is to get rid of the rivnuts, and tap threads into the forward face of the mounting tubes. Even though that will require a larger, non-countersunk mounting bolt, it may solve the vibration problem. Note that the forward faces of the mounting tubes are rather thin, so tapping threads into them may put one into the experimental mode, as far as longevity goes.
One may take a Dremel tool and open the orifice of the forward mounting tube (shown in the above picture), then, using a hemostat, insert a nylon locknut behind the forward face of the tube. A modified wrench will hold the locknut for tightening of the mounting bolt.
If a front license plate is not necessary, replace the rivnuts, dispose of the steel panel, and install a 1-1/4X1/8" aluminum angle, 20.5" long, polished. That gives an excellent aesthetic to the V-twin engine above it.