Tachometer sometimes not reading right.

[RVSSNAKE]

During our last trip I noticed that the tach did not seem to be reading right.
Then I noticed when I shut the engine off it would stay at about 800 rpm.
I did noticed that if I tap on it that it will go down.
Any ideas?

 

[SpencerPJ]

My tack on my motorcycle acts squirely like that at times.  Can't make any sense.

 

[Utclmjmpr]

Mine has been like that for years and I just live with it,,it will stay normal until the PacBrake sends the RPM up to 21 hundred or so,, then I have to tap the face to bring back down to "normal".>>>Dan