Here's how factory ignition-switch is wired.
Wiring-diagram of new-gen (I've fixed couple errors from manual).
And minimal kart-wiring diagram for putting Ninja engine into kart racer.
1. note ign-switch is triple-pole/single-throw with multiple inputs and outputs. One of which sends power to fusebox.
2. kill-switch is single-pole/single-throw with just one input and one output. Basically take power from fuse#3 and send it to ignition coils
3. in minimal kart-diagram, ignition-switch is retained and kill-switch tossed. Power goes directly from ignition-switch to ignition-coils without kill-switch in between. Ign-switch also turns on RR, powers ignitor and start-button.
4. If you remove ignition-switch, what turns on & off power to fusebox?
5. because kill-switch needs power from fusebox to turn on ignition-coils
6. ignitor and RR also needs power that's turned on & off through fusebox
7. clocks also needs power from fusebox
Requires lots of rewiring of harness after removing ignition switch. Basically every one of 7-wires that used to go to ignition-switch has to be re-connected somewhere else. And kill switch's already fully-connected with its 2 wires. It becomes paradox of chicken & egg. If you go back in time and kill your parents (remove ignition switch), how are you going to create yourself without them (power kill-switch)???
In end, I got that Woodcraft harness adapter InvisiBill linked to. Then removed ignition switch, kill-switch and start-button and replaced with just this.
