Removing lighting coil on a magneto?

[DANP]

If my magneto has an ignition coil and a lighting coil and I am choosing to wire the bike without any electrical system is it a problem to remove the lighting coil from the magneto if I am not using it? Would it throw the balance of the flywheel off?

 

[nrcb125]

What bike are you working on?

What purpose does removing the lighting coil serve? It might save a few ounces on wire, but it doesn't add any extra stress on the electrical system and you can simply leave it disconnected if you don't want to run lights.

On my CB125S, when you switch the lights on, the lighting coil is physically connected to the electrical system before the regulator/rectifier so more power is available to run the lights.

You can simply wire the coils together and not hook up any actual lights if you need the extra power for something else. It won't hurt anything. Or skip this step and not worry about hooking up lights, like you've planned. Make sure to get a regulator/rectifier for your electrical system. Ones from a scooter are cheap and can be more than enough for a small bike. This is what I did to "convert" my 125 to 12V.

Do not unwind anything on your stator/magneto unless you plan in rewinding it.

 

[DANP]

Cool thanks. I just didn't want that extra wire coming out of my motor and not being hooked up to anything else. So If I wire both coils together and then connect to ignition coil will it provide a more powerful spark?

 

[Rich Ard]

Yep. You'll be able to light a cigar from it...once.

You can tape off the extra wire after dipping the end in liquid electrical tape.

 

[nrcb125]

Cool thanks. I just didn't want that extra wire coming out of my motor and not being hooked up to anything else. So If I wire both coils together and then connect to ignition coil will it provide a more powerful spark?

All wiring the stator windings together does is allow more current, and consequently more power to be available to the electrical system. This is all done BEFORE the regulator/rectifier and the actual ignition system (coils, plugs, etc) does not change. Check your wiring diagram.

Wiring them together means you could hook up a headlight, or a blender, or whatever you want. For example: if your system puts out say 60W from only the ignition coil, the lighting coil will add ~40W to the total power available so you can run a 35W headlight with a few watts extra. No headlight? Then you can run 40W worth of whatever.

The spark will not be more powerful. This is because the ignition system has not changed; the same components are being used. You would have to change either the spark plugs or the ignition coils themselves.

What bike are you working on?

 

[DANP]

Bike is a 1970 Harley Davidson dirt bike. If I am correct I can just wire a toggle switch in-between the magneto and the ignition coil to kill it? I'm trying to make a very stripped down fail-proof trail bike, no lost keys, bulky lights, horn...