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Update on my Breva IE 750 conversion - October 2013

by

Bob Gilpatrick

The Breva IE 750 motor is a fuel injected small block Moto Guzzi V-twin motor, in my case a 2007, which will replace the Citroen 602 motor that I have been using for about three years in my Supersports. The Moto Guzzi carburettor engines are becoming quite common in our Grasshoppers as you can see if you look at the owners/builders reports. There appears to be only one fuel injected conversions up and running to date, Mark Saperstein in Arizona. Mark hasn't given out much information on his conversion. It would be interesting to see how he solved some of the problems of his conversion, a big block fuel injected engine.

I finally have my engine mounted with the throttle bodies connected. I also have fabricated a suitable throttle cable that operates the throttle bodies. My next effort will be to connect the electronics which operate the fuel injection. I bought a complete Breva IE 750 electric harness but have found the harness does not fit as it did on the motorcycle. I have completely separated all of the wires and plugs in the harness and am now extending the wires to fit. The harness did not come with the numerous relays and sensors that are in the fuel injection system so I am locating and buying them as they come up on ebay.

The first problem I ran into when I tried to install the Breva motor was that the throttle bodies' mounting position on the motor interfered with the gearbox/motor hangers, especially on the left side. The adapter kit I bought from PMC fit perfectly but I had to design and have machined supplemental spacers to move the motor 11/2" forward so as to gain enough space to allow an intake manifold to be extended from the relocated throttle bodies to the intake ports on the motor. Each cylinder of the 2007 Breva IE 750 motor has its own throttle body. The left throttle body is operated by a cable connected to the accelerator. The right throttle body is slaved to the left one by an adjustable link. Both throttle bodies are synchronized to operate together through this link. Further, the left throttle body reports its position to the system's computer through a position sensor mounted thereon. I relocated the throttle bodies to a plate I welded to the frame member where the 602 coil was mounted previously.

In order to connect the throttle bodies to the motor intake manifolds I used two 1¾" OD aluminum 60 degree angle bent tubes and two 45 degree bent 1¾" ID flexible silicone tubes fastened with jubilee clamps. All of these components were obtained from ebay sources.

I am satisfied that the extended mounting of the motor will work. The Moto Guzzi motor with flywheel, clutch and new spacers weighs about 120 lbs. and shouldn't put much more strain on the hangers that the Citroen did. The next step will be to reconnect the electronics of the fuel injection system. The original wiring harness did not fit so I took it apart, completely, to extend and relocate all the relays and other electronic components. I am going to split the systems so that the original Supersports starter, lights and horn will be one system and the Moto Guzzi fuel injection system will be another separate system. Both systems will share the alternator, voltage regulator and battery. So, I have several weeks of making up a test electric harness and then making up the final wiring harness. I just hope the motor will run when I finally get it hooked up to fuel and electrics.

For fuel I have installed a high pressure electric pump which will be part of the Supersports side of the electric system. I have maintained the original plastic fuel tank and will attempt to get the fuel level sender to work with the Moto Guzzi fuel level indicator. I am also trying to integrate the Breva 750 instrument cluster into the instrument panel.

Here are some pictures of the installation, so far:

This picture shows the spacers I had made up by a local machine shop. The large ring is made from 6061 T6 aluminum, is 1½" deep, and will be placed between the motor and PMC's gearbox to motor adapter. The smaller piece is machined from steel, is also 1½" deep, and will be placed between the crankshaft end of the motor and the PMC crankshaft to flywheel adapter.

These pictures show the back of the MG motor with PMC crankshaft to flywheel adapter on top of the 1½" steel spacer. The flywheel and clutch will attach to the PMC adapter.

The flywheel and clutch are attached to the PMC adapter atop the 1½" steel spacer. The green PMC motor to gearbox adapter is attached to the 1½" aluminum spacer which positions the motor farther away from the gearbox/motor hanger to allow enough room connect the throttle body intake tubes to the intake manifolds of the Moto Guzzi motor.

Relocated throttle bodies are connected to the motor intake manifolds. Throttle cable is connected to the accelerator pedal and the left throttle body bell crank. The left throttle body is slaved to the right throttle body with an adjustable link underneath the mounting plate. The throttle position sensor (yellow spot) is mounted atop the left throttle body.


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