Converting the Moto Guzzi to an Electronic Speedometer

About two tankfuls after I bought the Guzzi, the odometer pinion gears stripped. I tried to get the problem repaired but there were no parts available to fix the gear drive which left me with no reliable way to tell how far I had gone on a tank. The traditional cheapo Guzzi route is to use a bicycle computer, but that was a bit too ghetto for my taste. So, I switched the speedo and tech to electronic units from VDO.

The electrical side was pretty straight forward, I added a wiring harness to get power from a hot fuze and splice into the tach signal wire. Overall that came out very clean.

Mounting the instruments was also easy since the metal plate the mounted the instruments turned out to have the perfect ID to hold the VDO instruments. Unfortunately I could use the cover that fit over the back on the ITI instruments. I will have to fabricate another cover, but that will come later.

The real trick was to interface the transmission to the electrical sending unit. I chose a very common GM speedo sender which used a ver coarse 7/8 18 thread female thread. The Guzzi has a M12x1.0 male thread to attach the speedo cable. An few minutes with my lathe and I had an adapter made up. Here is a picture of the speedo sender mated to the transmission

One concession to reality I had to make was that to clear the throttle linkage I had to cut down the connector on the sender unit and connect wires directly to the pins on the sender.


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