Speedometer calibration?

Is there a way a way to calibrate the speedometer in a 2nd gen MM?
after installing my new gauge setup my speedo appears to be about 10 mph off. needle placement looks correct, so i am assuming that would only account for 2-3 mph tops.
when I was swapping the speedo element between clusters I noticed a small lever type mechanism attached to the spring for the speedo gauge. Is this an adjustment of some sort? It seemed a little loose while I had access to it so I can't imagine it would be able to keep a setting if that actually is it. Is the looseness in it a self adjustment of some sort that maybe it will just center itself over time?
Any help is appreciated.
Btw, that looseness I described is guaranteed to be the way it is supposed to be because both clusters seemed to have the same tension on that part.
after installing my new gauge setup my speedo appears to be about 10 mph off. needle placement looks correct, so i am assuming that would only account for 2-3 mph tops.
when I was swapping the speedo element between clusters I noticed a small lever type mechanism attached to the spring for the speedo gauge. Is this an adjustment of some sort? It seemed a little loose while I had access to it so I can't imagine it would be able to keep a setting if that actually is it. Is the looseness in it a self adjustment of some sort that maybe it will just center itself over time?
Any help is appreciated.
Btw, that looseness I described is guaranteed to be the way it is supposed to be because both clusters seemed to have the same tension on that part.