You might be able to wire that Engine Stop switch to run a relay to feed power to the ignition. I use a relay controled by the Engine Stop switch on my bike.
Use a common relay from most any where hook power from the key to terminals 86 and 30. Hook terminal 85 to the Engine Stop switch. Hook the ignition to terminal 87.
This way power flows from the key switch to 86 thru the relay out to the Engine stop switch. When the Engine Stop switch makes contact with ground it closes the contacts in the relay sending power from 30 to 87 and the ignition.
Just had a thought, is the Engine Stop switch a momentary switch, just on when you hold it pushed or is it an off/on type switch. If it has to be held down the relay idea will work, you would just have to hold the switch to run the bike. If it is an on/off switch that stays switched then it will work, the off my be on.
On mine I set it up so the stock engine stop switch feeds power to the relay and grounds after the relay.
The Engine Stop switch just controls the relay, the relay controls the power to the ignition. This way even if the Engine Stop switch gets a bit grungy the ignition gets full power thru the relay.
With no battery, I just saw that, this won't work.
Yep, check with Pete.