If you try to make your stock 200x stator charge the battery, you have to do more than just hook up the wire. The stock lights are AC, and the battery is DC. You would need to add a regulator. And you would need a switch so that the battery is not being charged when the lights are on. The stock stator does not have enough power to run the lights and charge the battery. You will burn it up if you try to do both.
I do not know if the stator from one of the early electric start trikes would fit, but if it did that would be a good option.
ATCnut
82 185s - sold
83 200x (hopped up)
84 200x (stock)
84 70 (lost this one to the DMV)
85 70 (soon to have lights, a foot brake, and CDI ignition)
84 200es (parts trike) - sold
85 350X (the best)
85 350X (siezed motor, dream of a poweroll kit someday)
85 250sx (frame was trash, got parted out)
86 250sx (the tractor)
86 250sx (a nicer tractor)
86 250sx (an even nicer tractor)
87 200x (parts trike, its really rough, a dog was chewing on it for a while)
87 250es Big Red (the tank!!)