I think you can still get floppy disk drives, assuming that Yamaha are using a standard floppy format. If you can read the floppy on a PC or a Mac that suggests a standard unit, then it depends whether the Yamaha item uses a custom or standard connector.

I had to replace the floppy on my old Ensoniq SD1. Standard connector, non-standard format. I had to get a very customisable TEAC drive (with a matrix of configuration pins) and fiddle until it worked.

And the excessive thumping of the keybed is usually to do with the strip that the keys hit at the end of the travel getting worn. There's a youtube video about it. I think you can get the strip off Yamaha.