Mattzmad wrote:Just got an hrc copy cdi unit through. Pluged it in and bike runs a dream. Revs right out but the tacho still says no.

It's not entirely unknown for the tacho unit to die. They can be replaced, as you will have noticed.

Worth checking continuity on all the wires from the plug to the back of the unit. Check the screws are all clean and tight. Take the back off and give a qyuick look for broken wires or solder joints.

All sorted. I have to confess I left the tacho unpluged post cdi swap.
PluggeD the old one back in just to prove its failed. And it has. Stuck in limp mode with no tacho reading.