This might sound crazy, but where the harness plugs into the CDI, sometimes that male pin down in the connector in the CDI box will get loose inside the box & break connection like on & off. Sometimes you can bend the wires of the harness around & pull tye them so as to put a bind on the connector & it will cause the pin to hold connection down inside the CDI.
Another thing, have heard of guys taking a real small screw type C clamp, putting it right in the middle of the CDI box, applying a slight amount of pressure & it would go back to working proper.
In the harness, the black wire with the white stripe, is the main ignition wire coming from the CDI box.
All this is just a get by though until you can buy new parts.
Neil