Did the hub feature a 'rear-seal', from here, it looks like the weather may have washed it out. I know the spring loaded hub seals can make it tough to R&R hub assys and make it difficult to re-pack the rear bearing. I always use great care when I encountor one on a hub. Most of the time its gotta be replaced, because they can be rough to remove(when there rusty, etc).

 As for that phono-graph loudspeaker, on the motorcycle, it must have been around in the time of Thomas Edison. Looks pretty sturdy, I dont see a braket. Although, one of those Conquistador helmets would go perfectly with that.  :)