Roger, you can pull the needle and re-insert it...
Tachs need not be accurate, you just need to know when to back off or shift when its pointing to SOMETHING. Use a test Tach that clips onto the coil and ground to determine ACTUAL Rpms and make a mental not of it.
OR...
You can remove and adjust the needle to point at the number that is indeed accurate at the PEAK RPM you don't wish to exceed... and where it rests when idle or off is of no real consequence. Kinda like a "shift-light" used on race cars... They don't care what the number is, when the light comes on, do something else!
If you are looking for accuracy with this stock gauge... you might go nuts by adding and subtracting weight on the needle or counterweight... or go even further with coil windings... But just remember, no ANALOG gauge is accurate throughout its full needle range or travel. A good compromise is OK and just knowing where it points when its idling RIGHT and what rpm NOT to exceed are the only real points you need to concern yourself with.
HTH...
