If you have a DC ignition system here are some wiring diagrams ... pages 8 and 9 for DC... looks like you need 12 volts from the battery to the CDI to charge it and then the trigger impulse from the stator to signal the CDI when to pulse the coil. So I'd be checking the clearance of the of the trigger coil pick up to make sure it's sending enough signal to the CDI and the output of the CDI to the coil. I don't know the values they should be for a DC system.
http://www.jr-richscooterdoc.com/Hel..._explained.pdf