KAWASAKI GT CLUB

AUTO TURN CANCELLING CIRCUIT ON GT750

Auto Turn cancelling circuit on the GT750

by Richard Axford

The Speedo cable turns the input shaft for the speedometer unit in the instrument cluster. The speedo unit also contains a small pulse sensor unit on the input shaft. This sensor is actually a small switch which effectively opens and shuts as the input shaft turns, giving approximately 12 pulses per revolution of the front wheel. This sensor therefore stopped working when Chuck's cable failed and started working again when he installed a new cable.

Referring to my partial circuit diagram enclosed ( PowerPoint file turncncl.ppt) I think you can see the operation of the system.

1. The sensor pulses are fed continuously on a pair of wires (Red & Light Green) to the Cancel Control Unit which is fixed by two screws under the frame top pipes, just under the rear of the petrol tank. ( Check that the multi-plug/socket connector to this Unit is CLEAN! My problem was caused by dirt in one of the connections.)

2. When the Turn Switch on the left handlebar is pushed to right or left, +12 Volts supply is fed to the Flasher Unit (making the indicators flash) and also to the Control Unit. The Control Unit now counts the pulses from the sensor, and after approximately 4 seconds plus 280 pulses (or 50 yards), +12V power is fed from the Control Unit via the White/Green wire to the Solenoid in the left handlebar unit.

3. The resulting current through the Solenoid causes it to activate and force the Turn Switch back to centre position. This action also cuts off power to the Control Unit and Flasher Unit, the flashers stop and you're ready for next time.