I did not write this , but give credits to the lad who made this. (BTW, follow at your own risk!)
Quote from book :
The TOS sensor, the same in the GT650 and GV650, turns the ignition off when an emergency happens such as excessive tilting or the tipping over of the bike. If the sensor is not working it will create a situation whereby after a short time of about 2 seconds after the ignition is switched off the injection pump is disabled and you cannot fire up the engine. When this happens, the display will always show an “FI” error. When this happens the sensor should be checked. Put the bike into service mode. There should be displayed error c23. This means that the sensor is faulty and needs replacing. If there is any problem with buying a new sensor, or the price of about $ 100 is too high, you can hand-edit the faulty sensor for the engine to run properly not display FI error. The cost of modification is only the purchase of two resistors in the price of .30₵ – .40₵ cents. The only drawback of this modification is that if you tip over the bike while running, the ignition will not be stopped.
DOWNLOAD / VIEW – 650cc Twins – Tip Over Sensor Mod (.pdf)