Topic: Trying to wrap my head around resistor plugs

[Dime]

I just order a knock off pair of Dyna coils in 5 ohm as well as the knock off electronic ignition.

I have a set of suppression wires left over from my dohc days. Right now I have D8EA plugs. Should I be running a resister plug instead with the suppression wires? I was never any good at this stuff.

Thanks, Dime.

[Dime]

I think I found the answer on an old post on here.

If the resistance is less than 5k in the wires I have to run a resistor plug.

Off to measure the wires.

[Deltarider]

If your wires are the graphite core type, I'd abandon them. On our bikes they are not reliable. The core can become brittle resulting in misses. There are plenty good alternatives.

[Dime]

If your wires are the graphite core type, I'd abandon them. On our bikes they are not reliable. The core can become brittle resulting in misses. There are plenty good alternatives.

Ok just have a couple questions. Do the graphite core become brittle due to heat or vibration? Harleys run them with no issues so I am guessing it is not a vibration issue. If it is a heat issue I plan to run them with a heat shield.

That being said if it is really not an option what wires would you suggest and which plugs with the 5 ohm coils and electronic ignition?

Thank you

[Deltarider]

The regular iron core. Amazing Harley applies the graphite core. Dunno what causes the graphite to become brittle: heat, vibrations, bending or a combination. A well known Dutch Honda guru (dealer/mechanic) once had them and had on and off problems. Just forwarding his advice. IIRC the resistor wires need to be of equal length which is a bit difficult to realise on our bikes.

[Dime]

I appreciate the advice and have no doubt that he may have had problems but I am going to give it a go anyway.

I played around with the wire lengths and got the resistance very close to each other. I am out nothing as I had all this on hand.

If nothing else it can be an experiment to benefit someone else.

[Dime]

It won't let me post the pictures all.at once but with the multi meter set a 20k ohm the four wires are reading between 5.43 and 5.92 ohm.

See if the picture will load of the wires.

[Don R]

 Other engines with resistor wires do not have equal lengths. Of course, other engines have replaceable wires and they aren't expected to last 50+ years. My ARD mags both had resistor wires on them, and one set says ARD on them so someone thought they would work.

[Dime]

Other engines with resistor wires do not have equal lengths. Of course, other engines have replaceable wires and they aren't expected to last 50+ years. My ARD mags both had resistor wires on them, and one set says ARD on them so someone thought they would work.

I will give them go anyway. Nothing ventured, nothing gained.

[Mark1976]

Other engines with resistor wires do not have equal lengths. Of course, other engines have replaceable wires and they aren't expected to last 50+ years. My ARD mags both had resistor wires on them, and one set says ARD on them so someone thought they would work.

It was my understanding that you're not supposed to run resistor anything with a mag? Yes/no...

[Tracksnblades1]

Other engines with resistor wires do not have equal lengths. Of course, other engines have replaceable wires and they aren't expected to last 50+ years. My ARD mags both had resistor wires on them, and one set says ARD on them so someone thought they would work.

It was my understanding that you're not supposed to run resistor anything with a mag? Yes/no...

That’s interesting.

 I just replaced the spark plug wires on my old Lincoln SA200 that uses a Fairbanks Morse mag..
It had solid copper core wires. I cut the one up that was snapping a 3/4 inch spark to the carburetor bowl..
The Lincoln dealer had new sets in stock 😇. A little bit different though, looked like the copper had been tinned, or they were stainless..

And the old spark plugs still going strong are champion D16 which I believe are non-resistor…
IIRC the Champion UD16 is the resistor plugs used with aviation magnetos so the radio sounds better…