There is no tach wire for ZX14 going to dash, it's sent thru CanBus along with water temp etc. Don't know why RacePack would say you wouldn't be able to connect to the -side of coil wire. Going to the inj should work also, many products pick up the signal from splicing to inj side also. Problem with doing that on Kaws is that when you twist throttle rapidly you will see a large increase in RPM even tho it really didn't. It's caused by the inj squirting more fuel simulating an accelerator pump affect. Kaw also shut inj's off when you shut off throttle which will show 0 rpm then. White with red trace is #1 coil signal wire. If you look for it in the harness you need to make sure you are splicing into the coil white/red because there is also a white/red that travels thru the harness that goes to the headlight. Another white/red that runs 12v to the injs and also to the rear of the bike to the fuel pump relay. Blue with red trace is signal wire for #1 inj.