I suspect that what's loose is the part you put your foot on. You can access the fasteners bt pullong up the rubber foor rest.

i have a 06/650 burgman and there is a loose part under my left foot..i can reach up and feel that it is loose and i can move it in and out but i can't see it.  I have put 18,000 km on the bike….I need to figure out the best way to access the part…where does one start removing the cowling..Any help would be appreciated..