Thread: Grounding a Magneto

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Hi all.

How would I go about grounding a mageto? I need this to shut the engine down. The magneto has two wires comming out of it a red and green and is activated by flywheel magnets.

Thanks alot,
-CJP

Ground the wire supplying the signal to the magneto with a mag kill switch...

By the way the magneto is for a mini bike not a car. Im sure thats important.

hmmm ok. looking at the diagram now... the red wire connectes directly to the key under "IG" and that is the only wire that goes dead if you turn the key from the "on" to "off" position. The green wire goes through the "E" on the key, to the start switch, through the battery, and finally to the starter where it grounds.

so i am assuming i put a switch on the red wire and connect it to the frame? Won't this blow the magneto?

Is a switch rated at 6-12 volts and 35amps ok?

Thanks,
-CJP

get a peice of metal, thin stuff, cut it and bend it and drill it so the spark plug can pass thru the hole, then bend the other side around so if you press on it, it will contact the spark plug wire... coat the top w/ spray undercoating, to make sure you won't get zapped... B&S engines did this for many years on go kart engines.

for a switch
It's fairly easy, your key switch will have continuity between 2 terminals in the off position, it will go away in the run position.. on a B&S engine, the mag shut down wire is black, and will run under the flywheel cover to the magneto


however if you have continuity in the on position and not in the off position, you don't have a magneto, it's a coil operated ignition.

alright i get the picture Matt167, but wont the metal just touch the insulation on the wire and do nothing? or am i missing something?

ok. well the thing is, my fault, i didn't tell you guys that i have taken out (not destroyed) the original factory harness because i have stripped the bike of all bells and whistles. All she will have is a frame, engine, brakes, a suspension, and a body, you know... the essentials

so all i am dealing with is a magneto all on its own. that is the ONLY electric component on the bike. makes me feel dumb that i cant figure it out i think i know how to do it but i don't want the magneto to blow in a cloud of smoke.

I have attached photos of the magneto in question.

Thanks again,
-CJP

the current will pass thru the rubber insulation and ground it, the rubber is normally thin enough.


that does not appear to be a magneto tho, it appears to be a magnetic pickup of some sort, but I'm not sure, maby like a self contained CDI ignition.

I'd need to know what the back of your switch looks like, and if ither of those wires get power in the run position.

Your wish is my command

PDF file

-CJP

Alright i think i got it.

I will find the wire that has juice when the engine is running. Attach to a switch to a ground on the frame. flip the switch and that should ground out the mag right? The engine runs with neither of the wires attached to anything. (see above for wire diagram and pics)

What do you think?

-CJP

yes. that will work. it will have juice when running, but will be A/C volts, make sure your meter is set to A/C

Thanks a million Matt167 I don't think ill ever forget how to do this!

-CJP