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how do u make a magneto? or how does it work? and does it send out pules or is it constant?

I'm working on my dirt bike and I am not getting any juice to the plug or anything else and I want to find out as much info as I can

NachoMahma5 years ago
. Magnetos are very simple and very rugged, which is why you find so many on dirt bikes, lawn mowers, and other small engines. They are also commonly used in drag racer engines (or were, last time I looked was in the '80s).
. All it does is pass a strong magnetic field (for your dirt bike, probably a permanent magnet mounted in the flywheel) across a coil of wire. The field induces current in the coil, which is directed to the spark plug wire and on to the plug. Very simple.
. But, as GuardianFox points out, building one to fit on your dirt bike is beyond the skills/resources of most DIYers. Your questions indicate to me that you are one of the many. Your best bet would be to repair or replace what the manufacturer installed.
. The first thing to do is inspect the spark plug. Most of the problems with small engines are caused by a fouled plug. You can check any automotive maintenance site and I'll bet there's more than one iBle that will tell you what to look for and what to do about it. If the plug is in good shape, set the gap. If it's in bad shape, your best bet is probably to replace it - cleaning a spark plug correctly is a bit of an Art. A lot of car mechanics no longer even keep the tools required - it's cheaper to replace them than spend the time cleaning.
. Inspection of the plug will also tell you how will your carburetion is working. If the mixture needs to be adjusted, now is the time to do it. Google is your friend.
. Now that you know that you have a good spark plug, put the wire on the plug and lay it so that the metal base is touching the engine block. Pull the cord and check for a hot spark at the plug tip. You may have to adjust the position of the plug a few times to get it right. Do NOT, I repeat, do NOT, hold the plug in place with your hand or any tool. Lay it on the block and get away from it. The magneto, if functioning, will put out several thousands of volts and it will bite you. It can kill you. If you have a good spark, the magneto was not the problem - re-install the plug and go for a ride.
darkmickey (author)  NachoMahma5 years ago
I don't know how good of a shock the magneto will give off but one time I was holing a spark plug wire on it so I could put it on some thin metal to see if it was getting spark and my buddy thought it would be funny to try and start it not fun my dirt bike is a 77 suzuki tc250 technically an enduro another question I had was can I hook up the magneto straight up to the spark plug or will I still need a coil I'm new to electrical stuff but its something I want to learn I appreciate the help
. The magneto is the coil. A "standard" automotive coil has two coils of wire, one to produce a magnetic field (primary circuit). In a magneto, the primary coil is replaced by a permanent magnet.
. Oops. Magnetos do have two coils of wire. The magnet drives the primary coil.
Yes it sends out pulses. as guardian said. You also have to make sure that your air gap between the magneto and the magnets in the flywheel is correct. Try loosening it off, putting a business card between the magneto and the magnet, lightly pushing down on the magneto and tightening it back up. If it's a newer dirt bike I wouldn't suggest making one. They will have timing curves and limiters built into them. But what the hell I guess it couldn't hurt.
For how it works : http://science.howstuffworks.com/question375.htm

To make one, you'd need a machine shop, tools designed to work with magnets, and all the materials involved. They're not overly complex, but it's honestly better to search for one to buy. You can probably build a working magneto as a science project, but honestly making the one that's right for your engine requires a little engineering know-how.

Yes, they produce pulses of current to your spark plugs.
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