hello all i have a 2001 dyna with  a hd tacko that only works intermittantly any ideas where to start looking thanks fxst 

How intermittent is it ?
Look at the wiring diagram and check for steady supply voltage across pin 1 + 2 on the Tach.
Check continuity of the pink tach signal wire from pin 3 of the Tach to pin 12 on the black ignition module connector.
If this checks out, it may be a faulty Tach. Likely not easily repairable if at all.