This is a hand drawn schematic that I carry in my tool bag of how I did mine. I plan to do a Wiki page with pics of a full install with thoughts about grounding.
On this CDI If its black, ground it to the frame/motor.
Ground your frame to your motor ( the closer to your spark plug the better)
Ground your motor to your frame.
Ground your seat to the frame/motor
Ground both mirrors to the seat/frame
Ground Ground Ground.
And when you are done grounding all that, Bolt a length of steel chain you your rear axel and let it drag on the GROUND
Sorry it's so hard to read and I got some chilli on it too.