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Is any one out there running one (or two) of these Dyna coils on their 70s airhead?


If so how does it work? Any starting isues? Do you know how they are wired internaly?

The reason I ask, I was running a different self powerd ignition system on the R75 motor in my conversion. It had a dual tower coil that was wired like this:


You can see there is no internal grounding of the secondary (output) side of the coil. As a result one spark plug acts as ground for the other. Or one plug fires from posative to negative and the other fires negative to posative. This is a nice simple design, but the moment you have one fouled plug, bad wire or bad resistor cap, you have no spark in either side.

Does anyone know if the Dyna coils are like that or do they have an internal secondary ground like a stock single coil, sorta like this:

Dunno the answer to your question directly, but a minute or 2 with a multimeter or a simple battery powered test light should tell you the answer.
(Need instructions?)
Hook one lead to primary terminal, and other lead to secondary terminal. if you get light or a reading of ohms say on the Rx10 scale, the answer is YES.
My GUESS is it is grounded in the inside...otherwise you'd have a polarity-sensitive spark and on one side you'd have a weak spark.

"Hook one lead to primary terminal, and other lead to secondary terminal. if you get light or a reading of ohms say on the Rx10 scale, the answer is YES."

On the coil I replaced (non Dyna)the answer was 6.5ish ohms.

I'm hopin somone will have a Dyna sitting in front of them to ckeck for me. I have been all over their site but can't find any technical info.

If you go here on the OMEGA website ( http://omegaignitions.com/pdf_files/dua ... ev01-4.pdf), you'll find the diagram for a Dyna dual coil. The primary side (between the two screws) measures 3 Ohm. The secondary side is something like >30kOhm between the two towers ... I think. Each side fires on its own independantly, but both triggered by the same input, the primary side. I am running one of those with my points ignition and Dyna Booster ... in a 90s Airhead.

What kind of issues are you expecting or afraid of? They will fail just like any other when their time has come.

"What kind of issues are you expecting or afraid of? "

My previuos setup was plagued with hard starting. Sometimes it cranked and cranked with no hint of life, and other times it lit right up. Because it was self powered I put it down to low RPMs. The same system on my R26 single starts easily with a modest kick.

It was very spark plug sensitive, and allways started and idled way better with freash plugs. I felt that just one slightly suspect plug would at times kill all the spark.

I eventulay turfed it and installed a Boyer and stock coils. It runs just like an airhead should now. But I'm haveing trouble finding a neat mounting location for the stock coils, hence I'm looking at the Dynas.

Stephen, have you ever pulled one plug wire and observed if you had spark on the others side?

Hmmmm, ... you mean that one time the engine started with one plug in and one plug out?

No, I didn't. But I assure you there is a spark on each side. I am sure I had both plugs out at one point and firing simultaneously but I can't remember it distinctively.

I'm a little lost on this. There was room for a pair of STOCK coils on either side of the frame, under the gas tank on all MY 70s Airheads. what's different on yours, Garnet?
Starting: I'm running a Dyna with a pair of Bosch Blue, (65 VW beetle) on the 78 R100s, and points/stock BMW coils on the 71-75/5. Both start really quick. The R75 will start with a nearly *dead battery using the foot starter...*not enough to spin the starter. The R100s won't start very nice if the battery is weak as the Dyna wants some serious voltage to operate. (But it has a foot lever, too)

Sorry Jean, I did not make it clear up front.

The bike is a 67 /2 with an R75 engine. The coil was inside the engine of a /2.

My previous ignition system had a tiny twin outlet coil that fit under the tank. There is not room there for two stock sized Bosch coils. When I changed everything over this past summer I was in a rush to get back on the road, so I hung the coils off each side of the battery. Now I want to tidy things up and am haveing a hard time finding a nice home for the coils. The Dyna coil is reported to fit under the /2 tank.

What I am trying to find out is, will the Dyna coil spark on one plug if the other plug or wire is not grounded. This was a common fault on early distributorless ignition systems on cars. One fouled plug or one bad wire would take out two cylinders. The mechanic would repalce the coil, when the problem was much simpler.

Hope that is a little clearer.