All the above tests are done at the plug for the CDI, another black box in front of the steering column, except for checking the black/yellow which is done at the coil end of the wire, with ignition on and CDI plugged in. The pulse generator is outside the flywheel, the alternator coils sit inside the flywheel.

 

OK folks I have posted the checks from merryman with answers to each.


1. Did you check that the black/white is live with ignition on?
Yes but it had a fairly low voltage. (around 2vdc) I have attached a pic of what I believe is the cdi if you dont mind humoring me.



This is the CDI right

2. At the CDI, the green/white should be earthed.
It is grounded

3. The blue/yellow comes from the pulse generator, so you should get a small AC voltage between it and earth when the engine is turned over.
Only a tiny acv but yes, its there
The black/yellow goes to the ignition coil. A much bigger AC voltage should be present between the coil end of this wire and earth when the engine is turned over.
NO VOLTAGE.

Now is this a no brainer? swap the CDI? or is there more to consider with my rather low voltage black / white wirre voltage??





low voltage. but better than no voltage right?

 

No, if you are not getting full 12v from the black/white, this powers the CDI, however you don't test the wires with the CDI plug connected, you take it off to make sure you get a good connection to the testers leads. I would use a test lamp for the black/white to ensure you are getting full power.You can't test the CDI itself but, if all the wires to it test right, the fault must be in the CDI.

 

ALrighty. So I think I have it figured. I disconnected the harness from the cdi box, and got a full 12v to it.
seems logical then that the cdi box has failed.
Ill pull the trigger and get one coming and see what shakes

thanks for the help