One potential source for your speedometer fluctuation may be "drag". Remove
your cable at both ends, clean and lubricate with a good quality cable
This should, hopefully, clear up (at least in part) your problem.
Herb in Grants Pass, Oregon
> My speedometer wanders about 10-15mph. Is there something I can do about
> this personally, or do I need a rebuild.?
> The electric tach is steady, but as it warms up the reading goes up, until
> it might be idling at "4000 RPM". I'm hoping that cleaning and tightening
> the electrical connections will help this one.
> It would be nice to have one or the other reasonably accurate <grin>
> Thanks in advance for any responses.
> Tom Zuchowski
> '61 Bugeye (with '67 instruments)
> Clemmons, NC