I recently picked up a 1971 CB350 twin. I am having issues with the headlight and am seeking some advice. The headlight is a sealed beam unit and it currently does not work. When I switch the low/high beam selector on, the tail running lamp comes on but no headlamp. I took apart the headlight and have three wires coming out off the bulb: green blue white. Which one of these brings power to the bulb? I know that blue is high beam and white is low beam and is green ground? Just wondering where I should start looking for power supply to the bulb.