1981 CT70 No Spark

Johnack15

New Member
I've got a 1981 CT70 that is not producing any spark. I have replaced the spark plug, restored the stator using a kit to replace the points, coils, and condenser. I've tested the output from the stator using a test light and it lights up when I turn the motor over. I have also tested the ignition coil using a 6v power source and when doing this the bike produces spark. When hooking everything up it doesn't produce spark though. I've replaced the wiring harness and I'm still having this issue. I have even tried hooking up the output from the stator straight to the ignition coil and was still not able to produce any spark. I'm not quite sure what else to try and would appreciate any insights.
 

hrc200x

Active Member
Double check the points gap is .012-.016 when the T on flywheel lines up to mark in the case (strait up). Feeler gauges can spring the points open when trying to test making it think you have them set correctly. The wire that hooks up to the points can't be grounded out on the metal frame work of the points, seems like there is a fiber washer that keeps it from doing that. Also make sure no wires on the condenser are touching the outer metal of the condenser, they need to be soldered to the middle portion only. Its possible when soldering the condenser it got too much heat and its bad, but wait on changing till its the last thing. How bad was your old stator?
 

Johnack15

New Member
If it is one of those issues with the stator still would it still be able to turn a test light on when checking for electrical output? The old stator wasn't able to turn on the test light but after replace the components it is.
 

hrc200x

Active Member
Would say it's possible one of those issues would still turn on test light. I'd think coils could be tested by ohming the wires but not sure which ones the leads would go on
 

Deoodles

Well-Known Member
Unplug the stator from the harnesses. Connect a multimeter lead to the pin that feeds the coil wire and the other lead to gnd. Turn on the key. I set my MM to tone and listen for the tone. You could set to ohms and read the meter. If you get a tone or reading other than open then you have an unintended ground somewhere.
 
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