was looking online for info on by passing the O2 sensor when I came across this which I have just cut and
the O2 sensor is not need any more since you are replacing the pipes. that system is used to protect the catalytic converter from damage due to a over rich fuel condition.
i do not like any of the after market fuel management system as they have a higher failure rate than the factory ECM and they real do not do as much as they claim by the manufactures of the after market parts. On the Yamaha's the base injector time is adjustable. You can make the bike run richer or leaner through the LED meter read out.
press both the "RESET" and "SELECT" while you turn the key to the "ON" position. Keeping them pressed for about 8 sec. you will see "DIAG" appear. Press "SELECT" once and you should see "CO". with "CO" on the LCD screen press both "RESET" and "SELECT" for about 2 sec. and you should see "C1" Use the "SELECT" or "REST" buttons to select the cylinder you wish to adjust. Then press both "SELECT" and "RESET" for about 2 sec. and you will see the current setting. Use the "SELECT" or "REST" buttons to make the mixture richer higher the number or leaner the lower the number.