Keep in mind, 1995 K11LT with BMW topbox and rear speaker ...
Last year, the molded plastic mounting bracket separated, and the left rear speaker fell out onto the seat. I epoxyed the parts to reinstall the speaker.
Later on, while washing the LT, I noticed a bit of flex in the lugguage rack, and the resulting movement in the top box. The rack flexes enough that I can move the box with my hand and see the movement in the rack. Naturally, I had never noticed it while riding as the box is behind me.
Two questions --
1. Is this just my luggage rack, or, do they all have a bit of flex that allows the box to shake?
2. What (if anything) have you done to alleviate the problem?