A tale of two magnetos

[opposedtwin]

I have had an FD-11 for many years. Love it all day long. Found another one on Craigslist a few weeks ago so i bought that one too. The minute I did, my old one started acting up (dropped a cylinder it turns out due to a disconnect at the spark plug wire/coil). Went through the magneto and now have good spark. Happy. Sorta….
The other FD-11 has the black coils. It does have spark, but notice the ground lead is mounted to the screw on the opposite side of the coil. Does it make a difference? I’m thinking not.

So, on to my question. I have the sweet timing fixture I bought from Frank Robb but am having trouble using it properly and effectively. I am using an analog multimeter and have set it up per the instructions: one lead grounded to the plate and the other on the points. My multimeter has two ohm settings: x1K and x10. When set up like this, on either ohm setting, there is continuity everywhere, ie: the multimeter needle is buried. No matter where i put the lead (on open points, on closed points or virtually anywhere on the motor) I have continuity. My points are brand new. My understanding is that when I open the points, the multimeter should read zero/nothing to indicate an open circuit, correct?

What am I doing wrong here?

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[chris-p]

Using the meter you have, you need to disconnect the leads going to the points to set them using the fixture.

No, doesn’t really matter which ground screw you use.

Also, take the plugs out while you do this for smoother operation of the fixture.

[opposedtwin]

Thanks Chris. Plugs are out. I’ll disconnect, was wondering about that.

[frankr]

With the wires connected to the points, you have a path from there, through the coil primary winding, and out to ground. So, it is the same as if you connected your meter lead directly to ground (continuity, regardless of points status).

[crosbyman]

http://www.youtube.com/watch?v=ga1Cjymj … e=youtu.be

this works also and/or simply adj. the points at .020 with the rub block on the high point of the cam lobe.

Joining AOMCI has priviledges 🙂

[fleetwin]

Ground lead location on the coil is not a problem…The problem is being sure to route the ground leads carefully so the flywheel does not rub on them…One of the ground leads in your top picture looks like it might rub, so you might want to relocate it to the farther screw on the other side…

[vintin]

Like Frank said you are reading through the coil primary winding.

I get about .7 ohm on a digital meter when reading through the coil primary winding and usually don’t disconnect the points. I worry that the torquing involved to reattach the points may change the point setting slightly.

[opposedtwin]

Thanks guys, now it works like a charm. Am stoked!!

Frank: never really knew too much about electricity but your directions are excellent. Wasn’t sure if my multimeter would require disconnecting wires or not. These timing fixtures are really, really nice. Thank you for making them.

Vin tin: I wonder about that too.

Chris: thanks for your timely recommendations, answers, etc. Much appreciated!

Fleetwin: I will re-route that wire.

Thanks!
Scott

[opposedtwin]

Another question regarding timing, etc.
On the first magneto, this is where the cam follower touches the cam when I twist the throttle. It should begin turning right on the mark on the cam, correct? I’ve got the cam adjusted in as far as it will go. What else can I do at this stage?

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[vintin]

If you look in from the front of the carb with your head low you should see a boss on the crankcase. When the hash mark in the throttle cam lines up with that hash mark the throttle butterfly should just begin to open. There are adjustments in the linkages or maybe adjustment made by loosening the bolts that hold the throttle cam in place, depending on year and model. My understanding and my experience leads me to believe this is a rough setting and a little one way or the other may result in superior performance. What you are really doing is determining where on the spark advance curve the high speed jet starts coming into play adding it’s input to the low speed jet.

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