1985/86 shadow 1100 coils

[SpiffyCat]

I have a problem with my coils on a 1985 shadow 1100. The rear coil seems to not
Be firing. I can take loose both spark plug wires off the rear cylinder. And there is no difference in the way the engine runs. Here is what I have done.
I took an ohm meter and checked the resistance of both coils.
Both coils at primary connector are 2.4 ohms.
The pulse generator Blue 430 and Yellow 421.
The camshaft pulse generator 612.

Can one check the power leads going to the coil, while it is running?
For instance the yellow and black/white wires going to the rear coil.
Do they have a specified amount of voltage? Does the current pulsate?
Thanks

[93gc40]

at the coil 1 wire will have 12v with key ON. The other will pulse, as the motor turns. Swap coils, does problem follow the coils?

[SpiffyCat]

On the wire that is suppose to pulsate, can you get a voltage while bike is running?
I know if you can the voltage would go up and down. I think it is the yellow wire on the rear coil.
The pulse generators seem ok. Could the cdi box be bad?
Does anything else control the pulse, like a relay?
Thinks

[93gc40]

Pulse comes from the CDI box. Pulse generators tell the CDI box where the cam and crank are and when to pulse. Don't remember volts spec. I never had a CDI box fail and still put out a pulse. So if you get a pulse at the coil, I bet you OK there. Most likely issue is the coil died. Swap the coils. I would replace BOTH coils as a set. Do some studying there are aftermarket coil available, much cheaper than OEM.

[GrumpyOldMan]

Yah, the coil swap is the most positive test. You don't need to run the bike - just pull all the plugs and position them so they touch metal and will be grounded. Even a short spin of the starter will show sparks if the coil is good.