Re: keyed ignition
I think most keyed "ignition" switches are Normally Open (NO), which means the switch is off until you turn the key to close the switch and turn things on. The keyed switch I'm using is made for a scooter that I purchased online from a scooter supply store. It comes with several copies of the key, and the key stays in the switch when in the on position (it wont fall out). My switch is NO and has four poles, so I can control four things with the same switch. But it only has two positions, on and off, so I can turn four things on and off at the same time. I'll use one pole (two wires) to open or close the circuit to the CDI so when the key is off, the CDI wont fire the spark plug. This will keep someone from starting the engine without the key (or hot wiring the bike). I'll use another pole of the key switch (two different wires) to control a main relay that will disconnect the 12V battery I'm going to use for the lights, etc. When the key switch is in the on position, the main relay will close connecting the battery to the rest of the electrical system. I need the main relay because it's not likely that the contacts of the key switch can handle the current that the horn will draw (20 amps); therefore, I can't run the main power circuit through the key switch.
The horn I'm going to use is a regular motorcycle or scooter horn that I ordered through a local motorcycle dealership. They had a thick parts catalog they found it in. It was only $10.54 with no shipping costs, which was less than I could find online. The horn is smaller and lighter than a car horn, but still puts out about 130 db of sound. Since it draws about 20 amps, I'll also control it with a relay that is controlled with the horn button on the handlebars.
After trying lots of options I didn't like, I made my headlight form a 12VDC, 20 Watt landscape flood light, a 4" dia. Schedule 10 PVC cap, a stainless steel clamp, and some aluminum bar stock (see photos).