Speedometer error - reading high

[Richard Tool]

The speedometer on my Commando has suddenly started to read high , Any clues as to whether it may be the instrument , cable or drive ? Thanks in advance.
RT

 

[CanukNortonNut]

Smith clock or Veglia?

 

[ILLF8ED]

We used to call the speedometer showing faster than actual being “optimistic”. Is yours constantly fast or bouncing? It’s not hard to check the physical condition of the speedo drive…to be sure.

 

[CanukNortonNut]

I know the French clocks showed fast by 15 mph. I switched two of them out on my 74 and replaced them with Smith clocks.

 

[Richard Tool]

Smiths - original to bike and only started reading high recently. It doesn’t do it all the time but when it does it is not bouncing - needle is steady .

 

[ludwig]

They are adjustable:

 

[concours]

Smiths - original to bike and only started reading high recently. It doesn’t do it all the time but when it does it is not bouncing - needle is steady .

I'm thinking it's beginning to soil the sheets.
I would disconnect it until you get a chance to have it looked at.
I've oiled the input shaft bush with some success.

 

[Lineslinger]

I tell the police mine is pessimistic.

 

[Onder]

Tell that to the judge.....good luck.