Topic: Electrical fun

[elPedro]

Hi, just bought a '79 CB650X which has been stood around for too long!  It's my first four but as I've liked twins in the past it's very helpfully chosen to only spark on two.

Is this common?
I've checked all the obvious things I can think of (plugs/caps/leads all ok, coils ok, spark generators both working ok) and there is a current along the two wires between the connector block and the coils on both sides which, as far I can tell, only leaves the other three wires coming from that connector block on the spark generator.

Anyone else had trouble with these or can think of anything I've missed?  The problem is definately in the wiring to the right coil (as you sit on the bike) but I don't want to pull the loom apart (it's still original!) to find where those other three wires go...

Will post any updates but I'm not sure what to check next!!

Thanks for any help,
Pete.

[bryanj]

I have heard but not proved myself that the pulse coils do go down. if its possible to swap the wires over see if the HT spark swops if yes its a pulse coil if no its probably an HT coil

[JonnyHonda]

Which two don't fire, I assume it's similar to the CB750 and only has two coils each driving two plugs, so on sequence one spark is wasted. (I think thats right)

[elPedro]

I have heard but not proved myself that the pulse coils do go down. if its possible to swap the wires over see if the HT spark swops if yes its a pulse coil if no its probably an HT coil

Checked all the HT by swapping everything unpluggable!

Bang on with the pulse coils though - borrowed an electrical testy gizmo from the sparky down the road & there's no circuit through the yellow side so I'll be looking for a replacement.  Going to search the site for where I might find one; update when I can unfreeze my fingers!

Cheers for the guidance,
Pete.