speedometer
Pull your speedo cable out,
slip the cable out of the casing and grease it.
If the cable is slightly long shorten it just a little bit.
if the cable is too long it forces the speedo head forward.
where the speedo head assembly is peened or rolled over to keep the assembly together.
There are alot of shops that can rebuild or freshen up your speedo. and calibrate it as well. this is better than putting in another used speedo, why ask for more problems.
I used to rebuild speedometers many years ago at a shop here in Minneapolis.
If you can't find anyone local, let me know and I will get you some info to have it shipped there rebuilt and shipped back to you.