Acewell gauge

Hi guys, me again.  I am connecting an Acewell digital gauge to my 73 Z1.  The red wire in the schematic needs to be tapped into the “switch key”, which I assume to be the ignition.  The ignition has four wires, red, blue, brown and white.  What wire should I tap into?
Thanks in advance!,

In general on Kaws white is power from fuse to keyed switch.  Once the switch is turned on with key then the brown wire provides power to most of the systems on the bike other than lights witch are powered by the red and blue wiries.So I would splice into the brown wire.  But I am sure others will chime in.

Thanks gd4now, sounds logical!

Yes, brown is the ignition key switched 12 Volt power wire!

Thanks Scorocco, should have the gauge and headlight wired in tomorrow.  Thanks for your help!

The ACCURATE RPM reading/wiring will be the difficult part, don´t ask me about this horror senario!

We will see!  Instructions call for coiling the rpm wire around the plug wire or connecting directly to the coil.  Hope it works!

The coiling around the HT option may be less prone to the erratic readings that Scirocco experienced