Rotor Magnet size and diameter ?

[amoretti]

I have bought a number of stator/coil units and rotor magnets as well. All the magnets seem under size if one is going to install them together with .005 clearance between the rotor and the stator. Or is the stator too large in inner diameter?? Is this usual or is there a source of them that fits properly?? These are the Chinese CDI units of different manufactures. I want to use them to make a magneto for a small model engine

I have bought 3 different rotor magnets and all seem smaller than they should be to allow a .005 clearance with the stator. Is this usual or are bigger, correct rotor magnets available?? Source? Thanks, John

 

[Chainlube]

Hmm. I've always thought they were closer to a .020". Especially the ones that have been floating around my wallet for ages

Are we talking 2t or 4t mags?

 

[Gordy]

Are we talking 2t or 4t mags?

I believe 2 stroke

 

[Chainlube]

Hmm. I've always thought they were closer to a .020". Especially the ones that have been floating around my wallet for ages

This is the mag from a CG engine, I don't see anyway to change the magnets.

You're right though, a standard business card will fit all the way around it between it and the coil.

I just loosen the four screws to center the mag, slip a business card in, top and bottom, then tighten it back down.

 

[amoretti]

Maybe there is some confusion, maybe its just me, but I just measured some business cards, they are all around .009"
to .012" in thickness. Plastic credit cards are right at .032"-just sayin.

If you measure the stator tunnel and the magnet I think you will find the gap is .045" on each side. Apparently it doesn't matter much what the gap is as long as the magnets don't rub.

I wonder if @Wrench would explain how he shims the magnets out-this would be a good thing if it can be done without too much fuss.

 

[Wrench]

Maybe there is some confusion, maybe its just me, but I just measured some business cards, they are all around .009"
to .012" in thickness. Plastic credit cards are right at .032"-just sayin.

If you measure the stator tunnel and the magnet I think you will find the gap is .045" on each side. Apparently it doesn't matter much what the gap is as long as the magnets don't rub.

I wonder if @Wrench would explain how he shims the magnets out-this would be a good thing if it can be done without too much fuss.

I was thinking about 4 stroke style stators with magnets in the flywheel

 

[Chainlube]

Maybe there is some confusion, maybe its just me, but I just measured some business cards, they are all around .009"
to .012" in thickness. Plastic credit cards are right at .032"-just sayin.

If you measure the stator tunnel and the magnet I think you will find the gap is .045" on each side. Apparently it doesn't matter much what the gap is as long as the magnets don't rub.

I wonder if @Wrench would explain how he shims the magnets out-this would be a good thing if it can be done without too much fuss.

Yea, those are .010 average. It's enough to make a good field and charge the CDI.