It controls both the injectors and the coils, thus controlling fuel injection and ignition in accordance with the engine operating conditions detected by the following sensors:

The maps, which include ignition advance values, injection times, crankshaft angle for injector closing and all correction curves as a function of temperature and atmospheric pressure values, are stored in the Flash Eprom of the ECU. The above values are preset by the Manufacturer after testing the motorcycle under different riding conditions.

Tighten the bolts (2) to the specified torque (Sect. C 3, Frame torque settings).

Connector (1) is a 48 PIN connector.

The control unit controls injector opening by feeding current to the coil of an electromagnet which creates a magnetic field thereby attracting an armature and generating fuel spray. If we take the physical characteristics of the fuel to be constant (viscosity, density), as well as the injector delivery and pressure head (controlled by the fuel pressure regulator), the amount of fuel injected depends on the duration for which the injector is open. This time is determined by the ECU in accordance with the engine operating conditions. In this way correct fuel delivery in ensured.

For removal or refitting of the injectors, refer to Section L 6, Removal of the fuel injectors/Refitting the injectors.

To test the operation of the injector, use the DDS tester and follow the instructions given in the paragraph “Guided diagnosis”, (Sect. D 5).

Do not leave the engine stopped for a long time with the fuel circuit full. The fuel could clog the injectors and render them inoperable. Periodically, after lengthy periods without running the engine, we recommend adding TUNAP 231 to the fuel in the tank to help clean critical sections of the fuel circuit.

The stepper motor shaft is fitted with a valve which opens a communicating passage between two ports; one of these ports (2) is connected to the intake manifold of the vertical cylinder while the other (4) is connected to the intake manifold of the horizontal cylinder. A third port (3) is connected to the airbox.

The stepper motor simultaneously controls two by-pass ports having an air flow capacity of around 6 kg/h.

In order to compensate for the quantity of supplementary air supplied by the stepper motor and consequently deliver the correct amount of fuel, the ECU converts the stepper motor steps into angular degrees of the throttle: this system means that opening the stepper motor is equivalent to opening the throttle.

The influence of the stepper motor air flow is present to approximately 30° throttle angle; no correction is required for greater angles.

Strategy 1) controlled solely by engine temperature (stepper motor opening/closing is determined by engine temperature alone).

StrategY 2) controlled by engine temperature and status. This strategy is applied only in the engine starting phase; the system determines a quantity of steps, to be added to those of the previous strategy, which are immediately decreased to zero, in accordance with the number of engine cycles, once the system has detected that the engine has started.

The Lambda sensor (1), positioned on the exhaust pipe, transmits information to the ECU on the amount of oxygen in the exhaust fumes. With this information the ECU can maintain optimal control over the fuel‑air mixture.

The outer surface of the sensor element in zirconium dioxide is in direct contact with the exhaust gas, while the inner surface is in contact with the atmosphere. Both surfaces are coated with a thin layer of platinum. Oxygen in ionic form travels through the ceramic layer and charges the platinum layer electrostatically so that the platinum acts as an electrode: the electrical signal generated is carried on the sensor output cable.

The zirconium dioxide element becomes permeable to oxygen ions at a temperature of around 300 °C.

When the oxygen concentration is different on the two sensor surfaces, a voltage is generated thanks to the special physical properties of the zirconium dioxide. With a lean mixture the signal voltage is low, while with a rich mixture it is high.

Typically the change in signal intensity occurs when the air-fuel ratio is 14.7 to 1 (14.7 parts air to 1 part petrol), which is referred to as “Lambda 1”. This ratio is considered to be an indication of complete combustion, hence the name “Lambda Sensor”. therefore

The air-fuel mixture control system is managed by the lambda sensor, which starts to operate at over 300 °C: the ceramic material starts conducting oxygen ions at around 300 °C. If the proportion of oxygen starts to differ between the two ends of the probe, this generates an electrical voltage between the two electrodes due to the particular nature of the material. This makes it possible to measure the difference in oxygen content between the exhaust gas and the ambient air. Combusted gas still contains a residual amount of oxygen when the air-fuel mixture delivered to the combustion chamber is incorrect. This makes it possible to adjust the injection control unit to ensure the engine always runs with the optimal air-fuel mixture.

When refitting the sensors, tighten them to the specified torque (Sect. C 3, Frame torque settings).

The TPS is powered by the ECU to which it sends a signal indicating the throttle position. This information is an indirect measure of the engine load and is used by the ECU as one of the main parameters for defining the fuel flow rate and spark advance.

To check this component, use the DDS tester following the instructions given in the paragraph “Guided diagnosis” (Sect. D 5).

For renewal of the TPS, refer to Sect. L 6, Removal of the throttle body.

This sensor is of the inductive type: it faces the timing gear and is capable of “reading” the 48 teeth and the 2 gaps (each equivalent to 2 teeth) positioned 180° apart.

The signal coming from the pickup on the camshaft gear is used by the ECU to determine the engine speed and as a timing reference point.

To check these components for faults, use the DDS tester and follow the instructions given in the paragraph “Guided diagnosis” (Sect. D 5).

For instructions on how to renew the sensor and check the air gap, see the chapter “Flywheel-alternator” (Sect. N 8).

This sensor is powered by the ECU and provides information regarding the temperature of the aspirated air. The electronic signals thus obtained are transmitted to the ECU, where they are used to make corrections in accordance with the temperature reading.

To test the operation of the injector, use the DDS tester and follow the instructions given in the paragraph “Guided diagnosis” (Sect. D 5).

To remove the air temperature sensor, disconnect the main wiring harness connector (1) from the sensor, unscrew the retaining bolts (2) and remove the sensor from the intake manifold.

Refitting is the reverse of removal: tighten the retaining screws (2) of the sensor to the specified torque (Sect. C 3, Frame torque settings.

This sensor is powered by the ECU and it supplies information concerning the absolute air pressure in an area of the motorcycle that is not subject to turbulence. The electronic signals thus obtained are transmitted to the ECU, where they are used to make corrections in accordance with the pressure reading.

To test the operation of the injector, use the DDS tester and follow the instructions given in the paragraph “Guided diagnosis” (Sect. D 5).

Refit the airbox (Sect. L 7, Refitting the airbox).

Remove the spark plug connectors (1) from the spark plugs in both heads and remove the four spark plugs, making sure that no debris falls into the combustion chamber.

Tighten to the specified torque (Sect. C 3, Engine torque settings).

Do not use spark plugs with inadequate thermal rating or incorrect thread length. The spark plug must be securely installed. If a spark plug is loose, it can overheat and damage the engine.

An inductive discharge ignition system is used. Coil operation is governed by the M3C electronic control unit, which calculates the ignition advance. The power module (integrated in the electronic control unit) also guarantees constant energy coil charge, by adjusting the dwell time.

When refitting, tighten the bolts (3) to the specified torque (Sect. C 3, Frame torque settings).

To check the coils for faults use the “DDS” tester (Sect. D 5, Guided diagnosis).

To access the relay, remove the seat (Sect. E 3, Removal of the seat) and remove the right-hand fairing (Sect. E 2, Removal of the side fairings).

Disconnect the relay from the electrical system and apply 12 V (battery voltage) between contacts (86) and (85) (small contacts): you should hear a click that confirms that the internal electromagnet has switched.

Connect a multimeter to contacts (30) and (87) (big contacts) to check for electrical continuity (see Sect. P 9, Diagnostic instruments concerning operation of the multimeter). The resistance reading should be near zero and, if present, the audible continuity signal should be emitted. If this does not occur, the part must be renewed.

This model utilises a CAN line (Controller Area Network) which has made it possible to greatly simplify the lay‑out of the electrical system and consequently reduce its overall weight.

This network makes it possible to avoid superfluous duplications of the sensors on the motorcycle, since their signals are shared by the two nodes and hence the two processing units. The sensors are connected to the nearer of the two units (instrument panel or ECU), which then transmits their signal to the network so that it can be used by the ECUs.

The CAN line is composed of only two wires carrying series of digital signals, each of which contains precisely defined and decodable information. The nodes connected to the line (instrument panel and engine ECU) are equipped with hardware to determine when the signals are of interest to them and should be used by their processors.