Common problem. There is a disk inside the speedo that is spun by the speedo cable.
The needle at the hub of the speedo gauge gets "excited" by magnetic eddy currents caused by the rotation of the spinning disk that deflect the needle. Slow rotation, little deflection, fast rotation big deflection. The needle hub of the speedo indicator seats in that tiny hole at the center. In order to work properly, the speedo needle hub sits centered, but not touching that hole, so don't bend it when seating the parts back together.
Most likely, the speedo cable has worked the hub for the disk out of the speedo slightly.
The quick repair may be to unscrew your speedo cable from the back of the speedo and push the hub back in. This may fix your problem. You can do this by simply pulling your speedo cable, without dismounting it. Just give the hub a push with the end of a screwdriver. If you're a contortionist, or a good hand with a phone camera, you can actually verify this problem in place:
It may be that the disk has worked off of the hub by that amount, so opening the speedo to push the disk back onto the hub may be necessary.
The full fix is to remove your speedo and do the repair described in the great video made by FunkyLaneO on YouTube:
If you
do pull your speedo, do yourself the favor to replace the odometer gear as he describes, with the part info available in my thread:
Speedometer_Gauges_Removal_Tom.pdf
Removing the speedo entails removing the multi-gauge cluster and possibly dismounting the tacho for easier access. Seems daunting, but once done, it's not so bad the second time, (like if you fixed the speedo, but didn't replace the odometer gear... ask me how I know
).
To remove the gauges, you must create room for them to exit by prying up the instrument binnacle. Pay close attention to Michael Thomson's excellent write-up for the screws to loosen to make this possible.
Good luck!
