Dyna Coil Upgrade

[sixtysix]

Dyna Coil Upgrade
By Pat Kelly
4/10/2003


I was having a problem on my XS1100E with no spark out of my left coil. After testing the coils I determined that this coil was bad and it was time to replace them, so I bought some new Dyna coils. These are from Dennis Kirk.



Advertised as 6 volt, 1.5 ohm, 35,000 volt output. Tech adviser at Dyna said these would work fine.

Edit: What has been found to work better is the Dyna DC1-1 'green' coils. By using these, you can bypass/eliminate the ballast resistor on the '78-80 bikes and have a bit hotter 'running' spark (the later bikes come with 3 ohm coils). Same size/shape, so the install is exactly the same other than the minor wiring change for the resistor. To bypass the resistor (located on the left lower frame tube near the coil), simply unplug the two red/white wires from it and connect them together.

I removed my old stock coils:



Here’s a comparison between the old and the new coils:



As you can see when the Dyna Coils are mounted like the stock coils, the plugwires will point to the side (either inside or outside, no room to have the wires facing each other). Here is a coil with the plugwires facing rearward:



You can see that the plugwires contact the fueltank mount.
Facing forward wasn’t much better:



So I headed to the hardware store and bought some right-angeled brackets and some shorter fasteners.



These allowed me to mount the coils with the plugwires facing downward:



This routes the plugwires away from everything (like the fueltank).



It’s necessary to make some primary wires for the new coils. I snipped the original wires from the stock coils for the color-coding:





But new wires could be made-up if desired.

Next came the plugwires. I ordered the Dyna Wires to go with the coils. These wires had straight plugboots that won’t work too well, they stick out quite a ways



I went to the local autoparts store and bought some right-angle plugboots:



This makes a much tidier look:



The finished product



Another item I bought was Bosch Platinum sparkplugs #4218 and gapped them bigger than stock, .035” (1.12mm). I had the bike running slightly rich before this so I should be dialed-in.

As it turned out, the coils weren’t my problem. I ended-up replacing the ignition box (I wanted these coils anyway).

I am amazed at the increased power. It’s quite noticeable.

A follow-up problem I’m encountering is it’s now harder to start. I’m not sure if the coils are needing more electricity to fire them or if my battery is just going out. I love old bikes.