1914 Hedstrom magneto timing

[Tommo]

I think where people get confused is that where mags are marked 1 and 2 most assume that 1 means the front cylinder when in fact it is the rear cylinder
1 is the rear cylinder
2 is the front cylinder
Generally valve timing marks on vee twins are set with the rear cylinder at TDC on the compression stroke and before someone quotes an example that isn't timed like that please note that I said "Generally".

[rwar]

I had not messed with the cams, fortunately. I had only taken off the mag and didn't worry about where things had been before that because I thought I had sufficient information at hand to put it back correctly. Dumb move, I know.

This should be enough to get me going, and I really appreciate it.

Thanks,
Rich

[c.o.]

Well Rich.... you wouldn't be the first person to rip something apart thinking it would be a breeze to get it back together. I doubt there are any among us that haven't done something similar at some point in time.... live and learn I always say... Let us know how you make out.

[Tom Lovejoy]

Johnny agreed with Gene and Tommo, sorry I did not git a photo. He said on the big gears, match up those double punches. Also he said make sure your using the wide lobe on the cam for the mag to the rear cylinder. He also said as Gene, put a touch of paint on the gears when you git it right. Also mentioned you should really time both cylinders as stated. Glad to see this info as I have a 14 also, good luck and let us know how it runs when done :-)

[Tom Lovejoy]

One more thing, my notes are a little iffy - but I think John said the only gears that matter are the small ones, as too possition of timming ?

[indianut]

Since the mag gear has a strong key in it, and was working at some time, I would rotate the engine where it is to the point where the piston needs to be to fire, either front or rear, and then remove the idler gear(s) and rotate the mag to where it will fire the chosen cylinder. then I would play with the idler gears until they go in with a certain set of marks lining up, THEN I would remove the idler gears and grind the additional marks off. If I still could not make a set of marks line up, with the engine ready to fire properly, I would remove ALL of the marks and put my own on! I have run into a situation where someone used Indian gears, marked for Indian into a J Harley and I chased my tail for awhile until I figured it out
PS when running a Splitdorf S mag in an Indian the front wire is the rear cylinder!

[rwar]

Thanks to everyone for all of the excellent advice. I decided I was going to master this thing.

I watched the tappet activity and, knowing that the two cylinders would be 360 plus 42 degrees out of phase with each other, made a chart of the eight strokes which make up a complete engine cycle. There is no ambiguity when you look at that way.

From the chart I could tell which lobe was which on the magneto because of the distances between them - the rear cylinder fire follows the front cylinder sooner than vice versa.

I chose to use the front cylinder to establish the magneto orientation simply because its priming cup looked more likely to be removable and replaceable without problems. I put the front cylinder 7/16" before TDC and used an ohmmeter to catch the mag points opening on the front cylinder.

There was a half tooth ambiguity when I went to put the idlers in (the position before TDC wasn't exactly a precision measurement), so I chose to advance it and mesh. I then rotated until the marks I had originally thought were the right ones were pointing towards each other, and lo and behold they were in agreement except one tooth advanced. So I retarded it back that one tooth.

The only question remaining was which mag output was which. For that, a few seconds of camera phone video showed that they are swapped - the front wire goes to the back cylinder. The Dixie Magneto, as I understand it, is a Splitdorf product.

And she fired right up and purred like a kitten.

Thanks again, everyone.

[c.o.]

"Purred like a kitten" Now that's what I like to hear!!!