'78 FXS burning coils : V-Twin Forum: Harley Davidson Forums

drtybrd13 · 06-19-2006, 06:21 AM

My early '78 FXS is burning ignition coils,and I can't figure it out.
I've checked the wiring from the RUN switch to the coil, and from the coil to the points. I can't find any shorts.
I've tested my points per the clymer repair manual, and everything seems to be in order.
Could this be a problem with my points ?
I gotta admit, I don't know much about these early ignition systems, so any suggestions will help.

springer- · 06-19-2006, 08:58 AM

Burning out coils typically happens because the power is on when the bike is not running. This will over heat the coil and burn it out. If this happens after it has been sitting then I would check power to the coil when the bike is off or how ever you typically leave it parked. If this happens when riding then I would check the charging system and make sure it is at the correct voltage when running. It may be too high and burning out the coil.

Good Luck

drtybrd13 · 06-19-2006, 12:28 PM

First off, I really appreciate you responding to my post
I'm not really leaving the power on to the coil when the bike's not running.
I think you're right about it getting too much juice. If I turn the switch on, only for a few seconds, the coil just gets way too hot.
What do you think ?

Again, thanks a bunch for your help.Ride safe.
Charlie

springer- · 06-19-2006, 01:37 PM

It is going to require some testing. Do you have a Volt Meter? If not you can get a cheap one at radio shack that will do the job.

petelogan · 06-20-2006, 02:33 AM

Bad regulator would cause too much power to the coil when running. Not sure what could cause power to the coil with the ignition off unless there's a cross-over in the ignition switch maybe.

L.Linkert · 06-25-2006, 12:03 PM

Not at all scientific, I noticed that the coil run hotter on my older bike that has points ignition with resistor wires and sparkplugs.
I now run nonresistor plugs and solid wires, as the bike came with.
Probably causes static on Police radios but runs noticably better.

drtybrd13 · 07-11-2006, 03:13 AM

Thank's a bunch ,fellas.
I eventually figured the problem out. The old shovel' running like a clock now.
I haven't checked out the forum in a while, been busy moving to phoenix.
I'm presently attending MMI. I'll be in touch.

Again all replies greatly appreciated,
Dirty.

springer- · 07-11-2006, 08:43 AM

Quote:

Originally Posted by drtybrd13

Thank's a bunch ,fellas.
I eventually figured the problem out. The old shovel' running like a clock now.
I haven't checked out the forum in a while, been busy moving to phoenix.
I'm presently attending MMI. I'll be in touch.

Again all replies greatly appreciated,
Dirty.

And what was the problem?