[JC]

The CDI units require equipment beyond a basic multimeter to test. What are you testing it with?

Run the stator test:

Stator Test | CX500info.com

...and see what it says. Instructions are linked to at the top of that page if you need them.

Define "some maintenance" to the fuel system? What did you do regarding cleaning the carbs?

Do you have spark on both sides?

 

[JC]

From my notes you require an oscilloscope, variable AC power source and programmable waveform generator to test them.

The carbs usually require ultrasonic cleaning to effectively clean them, so I wouldn't rule that out as the problem yet.