Originally Posted by
xr2wishy
bugger all to do with gearbox, who ever told you that doesn't know what they are talking about, both are mutually exclusive
it's more than likely an old wiring issue with an earth that is causing issues.
if it misreads throughout the revs there is an adjuster under the rev counter to correct the reading multiplier (handy for changing to efi when you only have a single supply from coil pack).
do what i did and buy a stack one, mucho coolness
yeah second that it will be a dodgy earth. turn on your lights and see if the tacho moves when its ticking over normally. my red one used to go up by 500 rpm when you switched the lights on, and used to go up when you used the leccy windows too.