Gregory Bender

Voltage regulator wiring notes

Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models


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Charlie Mullendore of Antietam Classic Cycle recently brought to my attention a couple of notes I should make about wiring the voltage regulator.

  1. The voltage regulator must be grounded. As original, the voltage regulator (Magneti Marelli and Bosch) is secured to the motorcycle via rubberized mounts. The rubberized mounts help protect the voltage regulator from vibration damage. When I fit aftermarket voltage regulators, I continue the use of rubberized mounts. Of course, there is no path to ground through the rubberized mounts. Therefore, the body of the voltage regulator must be grounded. Some voltage regulator have a specific ground terminal; others must have a ground wire connected to one of the mounted holes. Typically I will ground it directly as original: to the top bolt securing the right side tool box to the rear fender. The need for a ground wire is applicable to the original voltage regulator as well as to all of the aftermarket units.
  2. Terminal 61 on Bosch voltage regulators is not used. Terminal 61 is used on Volkswagens to illuminate the indicator light on the dash. Moto Guzzis do not use terminal 61. Instead, the D+ terminal on the generator is used for this purpose. It isn't that you couldn't use terminal 61, just that there is no advantage to running a longer wire to the voltage regulator to get the job done.