No spark gs400

[Guest]

'79 GS400 I have has no spark. I've replaced plugs, checked points gap, and there's power to the coils. Took boots off and cleaned corrosion off the little brass discs. The points seem break contact when checked with my ohm meter. Was just wondering if that's a common thing for 'both' coils to go bad?? The condensers look like their fairly new, and I did clean up the points on it....

Frank

[JayWB]

Check the voltage on the NEGATIVE side of the coils, the side that connects to the points. With the points open you should read 12+ volts (battery voltage). With the points closed you should read very close to zero volts. If you do the coils are bad. If you read anything different find out why.

[tkent02]

Very uncommon to have any problems besides points, condensers and lack of power to the coils. Super reliable system if these are taken care of. The coils fail rarely, but two at the same time isn't going to happen unless someone hooked 220 to them or hit them with a hammer or something..

[Redman]

Try disconnecting the condenser for just a little while as a test.




.

[trippivot]

change the condensers

turn on the key and check the points with a test light and make sure they interrupt voltage.

power at coils good,
power at points good,
points flashes a test light at the "F" mark good,
resistor cap is not much over 8K ohms good,
wires not pulled loose or broken from coils good,

all that is left is the condensers

[Bueller]

Ok..it's been a minute..finally decent enough to spend significant time in the garage. So this is what I've found.
Battery voltage at coils, points do trigger test light at the other end of coils, removed a condenser with no change.
Even though it's unlikely in my mind that both coils are shot, it would appear that's what's happening. The only other thing I can see being bad would be the coil wire boots. I may try to find some replacements and see what happens. I'm kinda of leaning toward converting it to electronic ignition, and putting a Harley coil on it (3ohm, wasted spark), just cause I have 1 laying around. Haven't really checked into it, but I would think it'll be compatible with whatever ignition I put on it. Thoughts?

Frank