from the cagiva navigator manual
The throttle position sensor is situated on the N° 2 carburettor (edit: with 'carburettor', they mean 'throttle bodies').
This sensor is a variable resistance sensor and senses the angle of
opening of the throttle. In the sensor, the battery voltage is changed
to the relative voltage of the position of the throttle and is then sent
to the ECM. The basic time of injection of the fuel (volume) is determined
according to the signal voltage (outgoing voltage).
The voltage increases when the throttle is increasingly opened.
To obtain the appropriate signal from the throttle position sensor, the basic sensor position is indicated on the LCD
display panel. The malfunction code is indicated in three columns. In front of the three columns is an additional
column that indicates the position with an upper, middle or lower line. If the indication is the upper line or lower line
when the engine is turning at 1300 rpm, slightly rotate the throttle position sensor and adjust the indication to the
middle line.
Under normal conditions, the stop screw of the throttle slightly pushes on the butterfly valve and the indication is on
the middle line.
Preparation
1) Connect the special tool (mode selector) to the dealer mode coupling on the wiring and switch on the engine.
2) Adjust the engine speed to 1300 rpm.
3) If it is necessary, adjust the throttle position sensor by loosening the screws and rotating the sensor. Adjust the
indication to the middle line.
4) Tighten the screws to fix the sensor.