I’ve read a few conflicting reports on this, but is there a wire coming from the harness for a tach?  If so, which one is it?  I’ve looked over the wiring diagrams that doesn’t really show anything that is obvious to me and it’s not something I’m planning to do immediately but I’m starting to plan out my re-wiring and part of that is getting a tach installed.

On a somewhat related note, is it easy to replace the positive and ground wires in the harness?  I was having some problems and the mechanic that fixed starting issues decided, in his infinite wisdom, to run two new wires from the motor, through new holes he drilled into the side, to the battery and I would like to properly fix that (he claimed that both wires were bad in the harness but I’m skeptical).  I’m thinking that this was a bad idea because other components need to use those two wires (choke, ignition key, etc) for power so I now have to connect the original harness and the two new wires out of a preponderance of safety.  I suspect wires are wires, if I can open up the heat shrink and update the wires, I can get new heat shrink for the harness.