Ok, heres the story. I was riding, all ok, then bike started missing, sputtering, backfiring. If I gently ease off throttle, it smoothes out, but will start symptoms when increaase throttle. I nursed it home, thinking maybe fuel problem. I opened up the carb,(S&S super E), checked float, needle seat valve, jets, everything ok. I rolle throttle, observed plenty of gas going into throat of carb. Tried to start up, wouldn't even act like it was going to start, so now I'm convinced I've got electrical problem.
I'v determined now I have no spark to plugs. I checked wiring to coil, I've got 12 volts, so I pulled plug, hooked everything up, grounded plug to frame, bumped starter, ....no spark at gap. Oh, mine has double plugs on each head, therefore two coils. I did same procedure through both coils,...nothing, no spark at plugs. Also, I put ohm meter on plug wires to see if maybe open wire,...they're ok.
My question is.....is my diagnostics ok, should I buy two new coils, or is there something else going on here??
Seems odd that both coils would fail at same time ??
Thanks,...Jim

Oh, forgot to say, this is an '87 FLHTC, if it matters any....

 

It does seem weird that both coils would be bad. What about the ignition module?

 

I would check the ignition sensor in the the cam cover and the wiring to it. I'm not sure if they installed a after market one, but if you have dual sparkplugs there proply is a aftermarket ignition. I dought that both coils would go bad. Why do you have dual plugs any way?

 

Both coils being bad is HIGHLY unlikely.....Ignition module may be bad......Have you rode the bike recently in HEAVY rain ?

 

It was already set up that way when I bought it. I probably wouldn't have went that way, but, ..oh well.... I've ordered new coils. I'm tired of 2nd guessing myself, and am going with my first thought. We'll see I guess.

 

Yea both coils going bad is very unlikely.I had the same problem & it turned out to be the sensor.

 

check all ground wires

 

Good Luck but I don't think its the coils. I will keep a eye on this thread to see what you fine.

 

What happened to me a long time ago on my '90 FXRS, the cup for the ignition sensor came loose. The little tab came loose so only a small portion was left. Some times it would catch and if I was gentle could make it run for a while. Took about three weeks for me to hunt that down, now it's one of those things I am always checking. Just something else to consider.

 

Ohm'ing the plug wires don't mean that there good.
I'd try changing out the wires first there cheap and they git alot of vibs from the engine and the carbon core goes bad.