1980 Gs1100 Spark issues

[Guest]

My 1980 GS1100 had no spark the other day after sitting outside for a few weeks. In the previous weeks it would cut out at high rpm (7000+) It was cranking over strong for a while but still I put it in the garage and charged the battery just incase. With the battery fully charged, I have spark. However, I decided to check out my connections and wiring harness. In the process I discovered that voltage to the orange and white positive supply wire for the ignition coils would drop to 10 volts when I hooked up one of the coils. Hooking up the other coil individually did not cause the voltage loss. Would I be right in assuming that there is a fault in the ignition coil causing a voltage drop? Can this happen to ignition coils? Why does the voltage drop only happen with one and not both? (I bumped the started just incase to have it on a different crank position) Would the drop in voltage due to this and a not fully charged battery (but still cranking good) cause the loss of spark to all cylinders?

Thank you. Tom

[tom203]

" I decided to check out my connections and wiring harness."

You probably need to be more thorough checking/cleaning connections on these old critters. Sitting out in weather might have aggravated things.
As far as ignition coil voltage drop.... understand that when ignition is "on" , the ignitor box is allowing current to flow thru one ignition coil, so you get a drop. 10 volts is lower than I would like- try cleaning the ignition circuit's connections.

[thoogylives]

About 5 years ago I changed all of my connections and they seem to be holding up. I will double check them all though. With the voltage drop to the one coil, I was thinking of switching the inputs to see if the other coil would then cause the same drop. I imagine the bike would not start (I wouldn't try) but I can't see it hurting anything. Thank you for the reply.