Testing a CDi

[Almac]

Looking for any advice on how to go about testing a CDi. Bike is an RZV500.

I had the bike out for a few runs last year with no issues. I went to take it out for a final run of the year to empty the tank and it wouldn’t fire, so just stored it for the winter.

Just getting round to having a look to see what the issue may be and I don’t appear to have a spark from either coil. I’ve checked both the kill and ignition circuits, both coils, magneto, pickup and source coils and regulator. All appear ok, power to all circuits, fuses intact and PV functions.

I’m now suspecting the CDi is at fault, I’ve proven all the wiring to it and between PV controller and was now wondering if there are any static tests that can be performed on the CDi unit.

Any help would be appreciated.

[Jeff B]

The CDI's tend to be quite reliable. Unfortunately the only test I can suggest is swappping it out for a different one. Do you have the shop manual? Not sure if it has any tests listed.

[Almac]

Yeah, thinking my only option is to swap it. I may be able to get hold of a friends cdi.

Don’t really fancy buying a second hand unit, if it is the cdi I’ll probably go down the Zeeltronic route.

[phildu31]

+1.
Unfortunately, there is no testing procedure available for these CDIs.
They are very reliable, but if failure is confirmed, Zeeltronic is the best option in my opinion ( and not too costly ).

[Almac]

I’ll try a scope on the source coil tomorrow to see if I’m getting a pulse signal out.

[Almac]

Ok, done a little more testing today. No real success but I think I'm at the stage I need to swap out the CDi unit.

I've read through some old threads with similar issues, one problem that seems to occur is with the connection to the tacho via the (B/W) wire between the CDi and PV controller. I've checked this wire between each device for correct continuity and also between earth. Resistance to earth was 450 Kohm so seems ok.

I checked the output from the pickup coil with a scope, the pulse shape looked reasonable and similar to some examples I found on previous threads, have a picture but not sure how to post it. I've listed my results below, they may be of use to others for future reference. One point is measuring the pickup coil with a digital multimeter. I've read a few comments on previous posts that you can't use one and need to use a scope, a scope is better but a DMM can also be used as long as its 'peak-hold' response time is fast enough. I used a Fluke 89 IV, standard peak hold would give me 0.75V on the pickup but with the meter set for 'fast peak-hold' (250us response time) the value was 4.7V which was similar to what I obtained on the scope.

All voltages were obtained with all four plugs removed and hand cranking the kick-start.

Pick-up coil: 108 ohms: 4.3V pk-pk
Source coil: red/green 143 ohms: 61V: brown/red 20 ohms: 11V

I checked the orange output wires from the CDi to the coil packs, continuity was fine but zero output volts from the CDi.

[phildu31]

Right, you're good for a new CDI.

[Almac]

Just to close this one out.

I fitted a friends cdi today and got a spark from both coils so looks like it is the original cdi which was at fault.