Dyna S with stock coils - Risky?

[Guest]

I’ve been slowly working on a 1978 GS550. It’s running fairly well but is misfiring a bit at idle. On a whim I purchased a Dynatek Dyna S electronic ignition. I was looking at videos for reference on how to install it, and came across this guy (https://youtu.be/GhB5Ncn3DAs) who mentions a cracked coil causing a dyna S to overheat and burn.

is it safe to assume that I should not install this without getting new coils and wires? I’m fairly sure both are stock on this bike.

[Nessism]

Stock coils are fine. You might want to replace the plug caps and snip off 3/8" of the wire where the plug caps screws in. You can even pull the wire out of the coil although that sometimes turns into a project if the wire doesn't want to release and then tears. If you search the forum you will find photos and information on how to do this job. I recommend sliding a pin between the wire and coil and then squirting some WD-40 in the crack. Work the pin around so the WD-40 gets down into the coil recess. You have a better chance of the wire pulling free then.

[Isoparmesan]

What is the advantage of trimming the plug wires? Less resistance?

[Isoparmesan]

D5F16966-95AE-4385-AAB5-852AA16B2B13.jpgHere’s some pics of my coils. Looks like there are some minor cracks. I have no experience with this. Should I be concerned about them?

[Isoparmesan]

22CF64F6-CA14-4DD0-BDA0-1EBABA9FD824.jpgThis is the left coil

[fbody_mike]

What is the advantage of trimming the plug wires? Less resistance?

Your getting some fresh copper and new insulator for the screw in the plug cap to connect in to. Just a bettter connection after decades of weather and vibration.

[bwringer]

Those pics are too small to determine anything useful about the coils.

Nothing wrong with using stock coils and wires if they're in good shape.

If they're cracked, swollen, warped, showing heat damage, or physically damaged in any way other than minor surface dings in the plastic coating, then don't use them. Some folks are using coils from a later model like a Bandit.



Also, it's fairly common to find the resistors inside the plug caps have deteriorated. New plug caps are a cheap and very easy upgrade that can head off issues. Plus, the rubber seals will be in better shape and thus keep out water much better.