The engine on a kids ATV will not start. It's a Honda Chinese clone 110cc. There is a very weak spark at the plug when the plug is placed .010" from a ground point, but the spark will not jump the plug gap (new plug .025" gap). Backing up from there.. the coil is next, and then the CDI.

How can I determine the failing component? I have tested continuity and voltages. Open circuit coming off the magneto during starting crank there is 30V AC. That goes into the CDI.

I have a replacement coil and CDI. I tried both and still no go. I plan to try the coil again since I have cleaned up some wiring connections since trying the first time.

The CDI has 5 pins - ground (G), the magneto in (BR), and the coil side out (BY). One of the others is a "to ground short" for a safety switch (BW). It's open circuit unless the switch is tripped. And the other pin is for a wire coming back from the magneto also (LW). What is LW for?

Here is the wiring diag, http://motorxtremes.com/pdfs/yatv_wiring.pdf