Using ignition switch on KZ1000 to turn a relay on/off

When I say ignition switch here, I'm referring to the cylinder the ignition key goes into and turns to make a connection, not the electronic starter switch.

So, I purchased an AM/FM radio to put on my KZ1000. In addition to the red and black +/- wires, it also has a green wire labeled "ignition". Having played around with it on a bench battery, the green wire turns a mechanical relay inside inside the radio on and off to prevent it from being a parasitic draw on the battery when the bike isn't running. Thing is, I have no idea where to hook that wire up on the bike.

I've struggled with something similar to this with other accessories like a USB charger, and settled on using the running lights to switch a relay on and off inside my fairing, but that means I can't run the charger without having the lights on. Since this bike is a police bike, it has a battery isolator circuit on it for a secondary battery for running the electronics without wasting gas or wearing down the main battery. I've put a Lithium Iron Phosphate battery on that circuit that should be able to run the radio for 9 hours.

My purpose here is to go to the local drive-in theater, which is still open thanks to cars being great for social distancing, and the local drive-in uses FM radio so people don't accidentally drive off with wired speakers in their windows.

Anyway, I have no idea where on the bike there exists any place to tap into the ignition switch. Would I have to dismantle the actual ignition switch and attach it there?

How much of the police stuff is still intact? The police bike has extra switches (like the siren switch and pursuit switch) that you could use for this purpose and you could tap into it through the siren sub-assembly harness connector.

I'm not sure you would want to connect to the ignition switch. You may drain the main battery through some other load activated by the switch. Plus, it sounds like the only thing you want on is the stereo.
I would wire the stereo directly to the lithium iron phosphate. Just turn your radio off when you don't need it. This way you can leave your ignition switch off.
I'm assuming you need to hook the green wire to 12v positive (in which case i would just twist the red and green wires together).

Hopefully, the stereo's power switch kills most of the power to the radio. Though you will have a small drain for the memory function on the stereo for presets.

I'd put a weatherproof plug between the radio and battery if you want to disconnect the radio for winter storage to prevent a drain.

Also place a fuse on the radio's positive wires as close to the battery as you can...I set a car on fire for not doing this.
What model stereo did you get?

It's a cheap $60 Chinese one off ebay that has good reviews on Amazon. I'm not sure how hooking the ignition wire to the ignition switch will cause a parasitic draw when the bike is off. Also it won't turn on unless power goes to both the ignition and positive wires because the ignition wire goes to a relay inside the radio to prevent exactly that.

All of the police equipment is intact except the pursuit lights are white and all the other lights are amber. I use the bike for security and escorting both wide loads and funerals. The siren is intact but set up to only sound off an air horn. So I can't use those switches. Also those switches get power with the ignition off. I have a tendency to accidentally not turn things off, so if really rather not substitute a manual switch for the ignition key switch.

Again this radio has a relay inside it. If it's draw power when the switch is off, hooking up the ignition wire to the ignition switch to turn on that relay inside the radio, then why wouldn't the headlights do the same?

Again internal relay, so the radio isn't being powered from the ignition, just a relay. The wires, red, black, and green. Green is ignition to power the internal relay.

I knower I've repeated myself here as lot but... It seems sometimes I have to.

If I understand correctly. You can wire the radio direct the the battery, red wire, and it will not work unless the green wire has power. Is that correct? Then thinking further without the green wire powered there is no draw on the battery? All that said I’m not familiar with the KZP wiring but the non police KZ1000 has a brown wire that has one extra unused 4mm female bullet connection. It is ignition switched, you could use it to power the green (relay). Looking at pictures of the KZP hand controls the lights and police accessories have to be manually turned on. Again that said you could have the ignition on, off/run switch in the off position so your coils are not getting power and with all lighting and police assesories off the radio should function as the only draw on the battery. Please confirm all this independently before completing the install.

If you are using this at a theater, don't you want the bike turned off while being able to use the radio? To do that, you need a switch that ignores the ignition switch position.

If you want to use the radio with the ignition switch in the "on" position or the "park" position then that would be easy to do, but you will have lights on draining the battery.

The diagram I have shows two unused wires on the ignition switch labeled battery II and Tail III. You could use those wires to run your extra devices when the bike is on or in park.

IT also shows accessory wiring that is just fused to the battery, so it is live all the time.

How is your secondary battery getting charged, and where does it connect to the bike?

I solved the problem. I took the ignition key cylinder out, took the cap off the bottom of it, evicted a jumping spider that had taken up residence in it, and soldered a wire to the yellow wire and ran it to a double headed plug. One plug goes to the radio's ignition wire and the other to a relay I stuck in the fairing to provide power off the accessory wire so that I can have something else put on in the future, don't know what, and not have to worry about it.

I've also found that the secondary battery is enabled when the key is off, so I'd be drawing from the main battery. To remedy this, I've installed a bypass switch that applies power to the ignition wire on the radio (with a diode to make sure it doesn't go up into the key switch) and that automatically turns itself off when the ignition key is turned on. I also used a multimeter to verify that the secondary battery is being used for the radio.

Now I'm waiting for some new seals for the output shaft and shift lever to get here so I can replace my shift shaft and shift pedal linkage since it's worn down to the point that I'm faced with either replacing it or welding it. Bought two NOS shafts and 2 NOS pedal linkages, so I should be good for a very long time. I don't intend to ever sell the bike, so... yeah. Shift shaft seal's been oozing oil for a while now and since I'm replacing the shaft, I'm redoing every last seal on the plate while I'm at it.

Then I'm off to the drive-in theater.

I've also replaced the secondary battery with a smaller, lighter lithium ion that's provides 50 amps with 30 amp hours. It's a 25 watt stereo, so at max volume that's about 7 and a half hours of audio. More than enough. I've also installed a thermostat to the battery's lines so that if it falls below freezing, the battery will disconnect. Not like I'll be running electronics with the bike off in those temperatures anyway, but I do ride regardless of the weather, so it's important to not let the battery charge when it falls below safe charge temperature.

Glad you got it done. Thanks for the update