The airhead ignition is known as "wasted spark". In a "wasted spark" ignition set up, I don't think it matters.  Wasted spark is when both cylinders experience spark at the plugs each time the piston approaches TDC, and the spark generated on the cylinder that is on exhaust stroke is wasted. I can not imagine how dual plugging would have any bearing on any of this.

I have heard of some riders routing the lower plug wire to the opposite twin output coil as a hedge against a coil failure. If 1 coil were to fail, the good coil would be issuing spark to both cylinders under this premise. This would work because of the wasted spark scheme.

James, thanks for the response. Am I understanding this right; I can hook top and bottom plugs up to one side, for example the left side and then top and bottom right side plugs up to the right coil? Does it matter if the top plug goes to the front coil or back coil? (Also, I’m not actually sure which coil port is different?)

mark

My understanding is that you should be able to use any spark plug wire on any coil tower. What I don't know for sure is what goes on with the ignition trigger with the Dyna ignition. Maybe Richard Whatley, or another member,  can shed more light on this. If the Dyna system defeats the wasted spark feature, then it might be necessary to connect the plug wires for a specific right/left cylinder firing. If I were trying figure this out, I would wire one coil to one cylinder and the other coil to the other and see if the motor fires off. Never having owned a bike equipped with a Dyna ignition, I don't know for sure if the wasted spark is utilized, or superseded by the Dyna.

I believe I’ve resolved my question; can someone confirm I’m on the right track$

left coil upper port wire goes to right cylinder, top or bottom spark plug

left coil lower port wire goes to left cylinder, top or bottom spark plug

Right coil upper port wire goes to right cylinder, top or bottom spark plug 

Right coil lower port wire goes to left cylinder spark plug

✧ I have zero experience with the Dyna 3 ignition.

✧ I stand by Jim's explanation of plug wiring and the "wasted spark" setup that Airheads use. That makes your plug wiring correct, as you've explained it.

Hope this helps.

Your scheme for the plug wires should work just fine.  What I was trying to explain, in a somewhat clumsy fashion, is that with a wasted spark ignition, there is no wrong way connect the plug wires in the coils.

thank you !

I understand you can collect all those "wasted sparks". With the standard 2-plug system it's a barely break-even situation, but with your new 4-plug system you could fill a saddle bag on every ride. Then you can take those "wasted sparks" to the Recycling Center and actually sell them. Think about it. They've never been used and are in perfect condition. Just because the engine wasted them doesn't mean you need to. 

It's really the responsible thing to do. 👍 

I had a Dyna Ignition on my 78 long ago. Going off memory. The rotor “ring” that secures to the old point cam/advance unit has a single magnet imbedded at the outer circumference. There are 2 pickups placed 180 degrees apart that the magnet “pulses” as it spins. Dyna labels the 2 pickups as left and right cylinder, but that is really a misnomer. Since the ignition primary circuit connects the 2 ignition coils in series, the pulse from EITHER PICKUP fires both ignition coils. 

However, there is a benefit to having the the 2 pickups. One of the two pickups can be adjusted slightly on the mounting. This allows you, with a good amount of patience, to erase any timing error between the pickups. This is done with a timing light. Tweak the pickup position so that there is no double image on the timing marks. You are adjusting so that the coils fire EXACTLY every 360 degrees of crank rotation (180 degrees cam rotation). Once there is no double image, then the entire pickup assembly can be rotated and locked down to set the timing. 

@mark-creek 

You are correct. Sorry for my late response.

On my dual plugged, the thinking is that if one coil goes titsup (old aviation tech term) the remaining operable coil fires both cylinders. Sort of like having two mags on an airplane engine.

DS

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