1917 Indian PowerPlus - Dixie Model H Magneto

[Beemererik]

I am working on a 1917 Indian PowerPlus that has not run for a long time (probably decades). In the process of getting it to a point where I can attempt to start it I am working on the magneto. This bike came equipped with the Dixie Model H magneto. I could not find much info on this mag so I thought a couple of items I ran across might be of general interest.

When I started working on this mag, one plug would spark occasionally and sometimes you would see a spark jump the points. I replaced the condenser (it was original with a date code from the teens), plug wires, and plug wire brushes as well as two brushes that connect the coil to the plugs (four brushes total in this mag vs. three in a Bosch ZEV). After I did this I was getting spark to both plugs. What's interesting about this mag is the points are fixed in position unlike a Bosch ZEV which has a rotating points plate.

Now to the reason I am writing this note. I could not get the advance to move freely. It was very very tight. As I was researching the Dixie Model H's I kept running into guys offering a new base for this magneto. It turns out the base of this magneto is made out of pot metal and mine was warping and had several cracks in it. This was part of the reason for my tight advance movement. I have attached photos of the base so you can see the cracking. If you notice the base resembles a cradle. The entire magneto mechanism from the points to the output slip ring sit in this cradle. When you retard or advance the mag, This entire mechanism moves in the cradle from one side to the other.

[Beemererik]

These photos show the mag with the base replaced.

[gharper]

Beemerik,

You have discovered one of the weaknesses of the Dixie magneto! Indeed, replacing the base is usually the key to that problem. It takes a lot of careful fitting to get the assembly to move freely in the base, which is critical because the linkage that moves the mag for advance and retard is pretty light duty.

Just for some information, here is the reason the Dixie moves the entire assembly. In order to get the hottest spark, two things must happen at exactly the same time inside the magneto: The points must open at the exact same instant the rotating pole breaks the magnetic field. Easy enough to do when building a fixed spark magneto. However with a manual advance, this only happens at one spot. As the points (or points cam as in Bosch) are moved relative to the pole shoes, this relationship changes. Bosch, Splitdorf, Berling and all the others made a compromise and set the hottest sparking position at about midway between full advance and full retard. I guess the idea is that will give the best spark for starting. Any position other than that is a compromise, but things are forgiving enough that it all works. Dixie had the idea to rotate the entire magnet, pole shoes, points and cam assembly as one. This allowed that magic point of both happening at the same time to never change, yet still allow advance and retard of the timing. Pretty ingenious idea actually but it really complicated things. The pot metal base was the biggest issue, so good for you in taking care of that.

I recall talking to George Yarocki years ago about the Dixie magneto. He said he remembered his dad saying it was the worst magneto ever built, in fact if it rained in the next county over, your mag would quit!

Good luck with you r project!

Gene Harper