I'm not familiar with the 610 specifically but it is lean when using the O2 sensor. When installing the PCIII you disable the O2 sensor, which puts the ECU in a different mode that uses a richer fuel map. The PCIII then leans it back down (if it has negative numbers in the map). Due to the variable states of iBeat tuning on bikes in the field, a good PCIII map for one bike might not work at all for another.
