Since I've had my '87 Syncro the speedometer has had an annoying rattling
sound.  I took it to these guys:
www.speedometerservice.net

And it's now perfectly quiet.  They said the factory grease gets hard.  They
also did the "odometer fix" while they were in there, though it had already
been done.  Cost me $100 (fixed price I think) and picked it up the same
day.

Tom Salicos
'87 Syncro Westy EG-33