This upgrade circuitry handles the Field side or charging side of the Generator on the OEM 6 volt systems. Heavy number 10 wires carry the load for the charging side of the system.  
B&B Note: Always inspect the 3 position Headlight/Charging switch for correct operation. Inspect for overheating/burning and also make sure the 3.0 Ohm resistor is in tip top shape for correct operation! We offer the correct 3 position switch on an exchange basis or outright.