You can certainly upgrade to a 12V system. RR is the rectifier/regulator but on the older machines they used two components, either a selenium or silicon rectifer, and a zener diode for a voltage regulator (today the two are combined in a solid state unit). The silicon rectifer that you have in use has a zener diode combined with it rather than as a separate unit. It's rated for 6 volts so you'll have to swap it with a 12 volt unit. But it's only "half-wave" rectification unlike the full wave rectification on newer 12V bikes - the difference is that you only get half of the ac power from the lighting coil rectified (single phase) rather than the full wave where the rectifer is able to "capture" both positive and negative sides of the sine wave (3-phase). This means that there is less power available to charge the battery. You will also have to change the headlight, tailight, turn signal bulbs, horn, battery, instrument bulbs, and turn signal relay to 12V units as well. The switches (ignition, brake light, turn signal, etc. should not have to be changed - they should be able to handle the higher voltage (as well as your wiring harness). Changing the instrument bulbs should be quite easy for you. The bulbs sockets are mounted in rubber "plugs" and are pressed into the underside of the instruments. Simply pop them out, exchange the bulbs, and press them back in place. The original 6v bulbs were rated as follows: Tach lamp = 3W, Hi Beam indicator = 1.5W
Neutral indicator = 3W, Turn signal ind. lamp = 1.5W, Speedo lamp = 3W, All turn signal lamps = 8W (each), the headlight was a 6v 25/25W and the tailight/stoplight bulb was a 6v 3/21CP
Hope that helps a little bit.
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