Coil Interchanges Between GS Models/Years?

[bgk]

A few weeks ago I posted a tech question about coils, and I learned (from SquareDancerLynn) that some GS coils are 3 Ohm and some are 5 Ohm.

I suspect I may need new coils, because I?m not getting a fat blue spark when I visually check the spark firing across the plug gap (when I pull the plugs out of the cylinders, re-install the plug wires and ground the plugs to the engine casing).

I have a 1979 GS1000L, which has been updated with a wiring harness and electronic ignition from a 1981 GS850G. However, I don?t know/remember if the coils were swapped over.

I also have a spare set of coils that came off a running 1983 GS750ES.

Are coils from all these model/year coils interchangeable?

Will I ?hurt? anything in my electrical system by temporarily installing the 1983 coils, to see if my spark improves?

Is it possible to ?measure? and compare the electrical characteristics of the different coils with a multi-meter, either off or on the bike, and if so what is the correct procedure to do it?

Thanks in advance for your response.

[SqDancerLynn1]

the 83 coils shouls work fine
Before 1980 - points ign - 5 ohm
1980 newer 3 ohm- elect ign

[bgk]

Thanks Lynn,

I'll install the '83 GS750 coils this week, and give 'em a whirl.

[saaz]

Actually the points ignition bikes are 2-6 ohm primary resistance, 11-17k ohm seconday resistance. This is factory manual specs.