Yamaha CO Adjustment
One very cool feature hidden within some bike builds is the ability to ground one or two lines going to the ECU and thus render the stock unit partially programmable via the CO Adjustment Mode.
The fuel injected Yamaha R6, R1, and FJ1300 all have a feature like this. For the R6, by grounding "line 29" (and line 27 if needed) going to the ECU, the computer is driven into a programing mode very similar to as if the race kit wire harness has been installed and will allow limited programming to the fuel and ignition curves.
The difference between the kit computer and this programing mode is that the program mode adjusts the map for each cylinder by a simple vertical shift, the kit computer adjusts based on throttle position. You can see the exact reprogramming procedure for R6 on pages 24-28 of the factory race kit manual. Obviously, Yamaha owners, it pays to get the race kit manual.