Voltage regulator connections to the D+ terminal (Bosch only)

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

Updated: 

Charlie Mullendore of Antietam Classic Cycle brought to my attention a wiring connection dissimilarity amongst the Bosch voltage regulators.

Charlie noted that some Bosch voltage regulators secure the D+ terminal to the voltage regulator via a wide spade terminal; other Bosch voltage regulators use a 5 mm ring terminal. From a couple of photos Charlie sent, I did some digging and discovered the following:

  • I believe the voltage regulators that use a wide spade terminal to secure the D+ terminal are the earliest voltage regulators. The example photo Charlie sent shows a Bosch part number of 0190350055. This voltage regulator is rated at 25 amp.
  • I believe the voltage regulators that use a 5 mm machine screw to secure the D+ terminal are the later voltage regulators. The example photo Charlie sent shows a Bosch part number of 0190350068. This voltage regulator is rated at 30 amp.
  • All of the modern replacement voltage regulators I've seen use a 5 mm machine screw to secure the D+ terminal (both the mechanical and electronic versions).

To the best of my knowledge, both the Magneti Marelli and Bosch generators are 25 amp units. It makes sense that a 25 amp voltage regulator would be fit to it. Unfortunately, I cannot find any picture of a Bosch voltage regulator in the spare parts catalogs by which to perform a visual confirmation.

Who knows why the observed difference? It could be a commonly sold aftermarket voltage regulator? It could be fitted from the factory? The original battery was rated at 32 amp/hours, so a 30 amp voltage regulator would have worked just fine with it.

D+ terminals circled. Later Bosch voltage regulator on the left; early Bosch voltage regulator on the right.
D+ terminals circled. Later Bosch voltage regulator on the left; early Bosch voltage regulator on the right.

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.

Direct link to image

D+ terminal circled. Close up view of the 5 mm threaded boss on the later Bosch voltage regulator.
D+ terminal circled. Close up view of the 5 mm threaded boss on the later Bosch voltage regulator.

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.

Direct link to image

Terminals on the other end are the same, though bent and positioned a bit differently (later Bosch voltage regulator on the left; early Bosch voltage regulator on the right).
Terminals on the other end are the same, though bent and positioned a bit differently (later Bosch voltage regulator on the left; early Bosch voltage regulator on the right).

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.

Direct link to image