Stock points coils with electronic ignition?

My '77 KZ650 C1 with a '78 C2 motor has been upgraded with the electronic ignition off an '80 KZ750. It seems to work fine, but I'm wondering if the stock 4 ohm coils are compatible with the electronic iggy. Does anyone know if I can get by with the original coils, and if I need to replace them, how many ohms do I need?

Cychotic wrote:

My '77 KZ650 C1 with a '78 C2 motor has been upgraded with the electronic ignition off an '80 KZ750. It seems to work fine, but I'm wondering if the stock 4 ohm coils are compatible with the electronic iggy. Does anyone know if I can get by with the original coils, and if I need to replace them, how many ohms do I need?

If it's the factory electronic ignition (as it says in your signature), generally they came with coils in the 2.5 to 2.7 ohm range. If it runs fine, don't worry about it.

The electronic ignition had slightly less dwell angle which means the coils will have slightly less time to charge than they did with the points. The lower resistance coils charge faster.

This will only be an issue in the higher RPM range. If you can reach redline at full throttle under load, then you are fine. If not, then you may want to look into Dyna or Accel 3-ohm coils, or some other 2.5 ohm coils.

The bike hits redline just fine. Sounds like I should be ok with the stock coils. Thanks loudhvx, I was hoping you'd answer this one for me.