1st attempt at wiring an ignition system

N

Nbrakhage

New Member
After 30 years of being shamefully clueless about electricity I've finally decided to do something about it, so
I'm teaching myself all about the black arts. While I'm getting my mind around electricity I'm also building my
First motorcycle and I thought it would be a great exercise to draw up what I think is the most basic and minimal
Ignition system for my XT500 (single cylinder, magneto, points). I would be very grateful if anyone wanted to
Comment on my schematic and let me know why it would or wouldn't work. Since I'm a beginner I am starting
At the beginning...I am just trying to get the engine to turn on and idle, not ride it or rev it, just get it to run.
Once I learn more I can try to incorporate a battery, or capacitor, or regulator/rectifiers...of course
That's assuming this wiring will even work like this.
So thanks for looking, and please comment...for a beginner like myself any info helps!
 

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Ok, you're on the right track here, but that won't work, for starters the whole thing is upside down. :-P

For real though i see two problems with that diagram. One, without the r/r you are feeding the coil unregulated ac which will probably fry the coil and will spark unreliably if at all. If you replace the magneto in that diagram with a 12v battery (i like to use a car battery on the workbench with two long wires when i'm doing this) it would run, but that brings up point number two: wired like that, even with the switch off you have power to the points (contact breaker) which if you leave it sit and the points happen to be closed you have a short that will drain the battery and possibly fry the points, so feed the points off the wire after the switch that goes to the coil to fix that and you have a good start and it will run. I usually work with a cat battery while i work out the wiring and then tackle the magneto & r/r last that way you can test everything with a nice clean 12v and get everything ironed out before moving on to the charging system.
 
dam i was looking forward to seeing how to wire that Cat Battery up, finally a good use for cats, would have made the bike purr...
 
I think a battery made from cats would make the bike much too moody and temperamental for daily use; in fact i think we just figured out the secret ingredient to lucas' magic smoke, it would explain a lot.
 
Thanks Johnson, that was very helpful! So you're telling me the first thing I should do is make it to where the motorcycle has it's wheels on the ground and not in the air? Back to the drawing board I guess...

From what I understand a regulator REGULATES voltage, keeping any surges or fluctuations in check? And a rectifier converts AC to DC (or DC to AC)? Am I on the right track? By adding a regulator/rectifier I would be feeding the ignition coil regulated DC instead of unregulated AC? If that is correct then great because I understand it so far!

I think I also understand about the switch being placed AFTER the points....If I had a continuous source of electricity (like a battery in the circuit) and the bike was sitting over night with the points in the closed position then the electricity would continue to flow through the circuit and damage the points or drain the power source? Are you saying that would happen even with the switch in the OFF position or it would only happen if I left the switch ON? Either way, moving the switch from AFTER the points to BEFORE the points would correct this?

A condenser....I think I already have that along with my contact breaker. I didn't add it in the diagram because I thought that the condenser was always included with the contact breaker. My understanding of the condenser is that it provides a place for the electricity to flow into while the points are open, then once the points close (completing the circuit) the electricity that just flowed INTO the condenser flows back OUT and back into the circuit?

Thanks again for commenting, just from what you said I have a slightly better comprehension of it all. I would like to consider your suggestion of adding a battery (my system is a 6V though) to test everything without constantly having to kick it over (to turn the magneto) When I get a minute to think about it I will draw up a diagram of how I think I should wire it....would you have a look when I post it and let me know if it will work?

Oh, and it wouldn't hurt my feelings at all if we used cats for batteries. Just grab the neighbors, attach the positive and negative, and power your portable margarita machine all afternoon!
 
The internet is a little like electricity to me....I use it even though I don't understand how it works, and when things don't work right I just have to live with it. So when I attach a picture and it flips upside down I just go with it. The good news is that if you click the picture it loads right side-up! (at least on my computer)
 
The rectifier converts the ac from the magneto to dc to be used by everything on the bike. The regulator on a magneto bike burns off the extra voltage, without it the magneto would make enough voltage to fry everything on the bike. The condensor is a capacitor; it cusions and smooths voltage spikes from the points. In most cases an engine will run without the condensor, but it improves reliability and reduces interference from the ignition from wreaking havoc the rest of th electrical system. I always use a battery when wiring a bike even if it's not going to have a battery when i'm done. The idea is using a battery to provide a stable voltage eliminates the variables of the charging system so if say your regulator is fried, you won't be chasing your tail wondering why the ignition won't work, then later after you remove the battery and wire the charging system and something goes wrong you know where to look, trust me it prevents quite a bit of head scratching. On a six volt bike for temporary troubleshooting use, why not use a cheap lantern battery (the big square brick one at the hardware store) it's not rechargeable but it's cheap and if you don't use it to crank the bike over it will last long enough to get things sorted.
 
The way you have the circuit drawn up the switch is neither before or after the points, it doesn't affect them at all. you want to disconect the wire going from the points to the switch and connect it on the other side of the switch with the wire that goes to the coil, that way when it's off it cuts the points and coil out of the circuit preventing that short, which works exactly like you described, it's worth noting that if you leave the switch on, the points can still short to ground, kill your battery and or melt themselves, this is normal and can happen to any bike with points even with factory wiring, so don't leave your ignition switch on with the engine not running.
 
One more thing, the regulator does NOT do a good enough job of suppressing surges and spikes from the magneto, that is usually handled by the battery and is what the capacitor does when you eliminate the battery.
 
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