Shaky Speedo

[MotoPsyche@aol.com]

For the year I've owned my '61 TR3A, my speedometer wavers at any particular 
speed, rather than holding steady.  There might be a five mph swing as the 
needle floats up and down, with no particular rhythm.

Any ideas what's up?  Does this sound like a speedo issue?  Cable?

Thanks for any clues.

Bill Stagg