MZ SM 125 Swapping the CDI Box

[Far Far Away]

Please Help …MZ SM125 – no spark – new plug, coil meters ok, but have also swapped out coil and high tension lead. Position sensor cleaned, meters ok, and sends over 1Vdc to CDI, battery tested & charged. All Gnds metered, all wires metered ok. No shorts. Original CDI unit not giving AC to coil, so found another DC CDI (Kawasaki D Tracker- look like GY6 unit).

First installed the new CDI as in attachment, and got spark, and bike started and ran for 10 minutes ok. Then no spark again.

Have tried connecting Position sensor Gnd to the CDI unit Gnd, knowing that the coil Gnd is to frame as well. – No spark, no AC from CDI coil connection.

It looks to me that this CDI unit has failed ? The issue is if I get another, will it too blow up ? I am confused re the position sensor wiring, GY6 has one wire going to CDI, so the other must go to Gnd ? MZ SM has both wires to the CDI unit – I can only assume one is connected to Gnd internally ?

DC Cdi’s are hard to find, and MZ SM Cdi’s are only found in Germany. I cannot convert to AC as that would require locating a suitable stator that would fit ??? What is my problem ? What should I try next ?