Are these coils dead?

[maclariz]

Just testing my coils to see if they are the cause of the misfire on the GS400.

Primary coil winding resistance:
4.5 ohms for both (nothing strange there)
Resistance between primary terminal and the plug wire (i.e. between the primary and secondary windings) ~ 8.5 k ohms
This latter reading has me worried. I thought that the secondary windings should be insulated from the primary windings (i.e. infinite resistance). Clearly not the case here. Could this be the cause of my firing problems?

[Jaguarjoe]

Just testing my coils to see if they are the cause of the misfire on the GS400.

Primary coil winding resistance:
4.5 ohms for both (nothing strange there)
Resistance between primary terminal and the plug wire (i.e. between the primary and secondary windings) ~ 8.5 k ohms
This latter reading has me worried. I thought that the secondary windings should be insulated from the primary windings (i.e. infinite resistance). Clearly not the case here. Could this be the cause of my firing problems?

You're right it should be infinite between primary and secondary. This could very well be your misfiring problem if the insulation is breaking down.

[robertob]

Not quite - Primary and secondary are both grounded through the same point. So if you measure from plug wire to primary positive you're measuring both coils. 8.5k sounds about right...

[maclariz]

Not quite - Primary and secondary are both grounded through the same point. So if you measure from plug wire to primary positive you're measuring both coils. 8.5k sounds about right...

Great to have someone who understands these things on board.