12 Volts conversion

Finally, there was light!

The 6 V A/C lighting of the XR500 and XR500R is notoriously weak.

At the front we find a D/C bulb with dual filament and a Zener diode in its base to rectify the 6 V A/C current. Only one of the filaments is used.

At the rear, a tiny bulb for symbolic presence.

Many of us would love to use the later XR500R 12 V glass lens at the front for safer night riding.

What is the simplest way to get 12 V out of the 6 V set up? Searching the Web you can find all sorts of tricks, most of them have not been tried by their authors.

I tried this one by Grego the XR500R wizard, with several coils to no avail.

After researching all sorts of other possible set-ups with aftermarket regulators-rectifiers and capacitors, i settled on a very simple solution.

Material needed:

  • one triple coil setup from a XL500S
  • one 12 V regulator from a XL500R


  1. Remove trom the triple coil set up the small copper coil and toss it in the bin, you don't need it.
  2. You are now left with 2 coils, one with a black wire that feeds the CDI with up to 50 V, and one with a white wire that will give up to 20 V A/C
  3. Connect the white wire to the white/yellow wire of the XL500R regulator + the wire(s) feeding the front AND the rear lights: yes one wire will feed 3 items, fronte, rear and regulator
  4. Connect the green wire from the regulator to the ground
  5. (Of course connect the black wire from the stator ignition coil to the black wire of the CDI and sort out the CDI + ignition coil + spark plug set up)

Result: 12 V A/C for the lights