Worst part, no check engine light on but two DTC codes p0134 and p0154. That means something about the O2 sensors are open. The bike is completely stock right now so no tuners.
P0134 Front Cylinder
If the sensor voltage does not come down to a normal operating range after a calibrated amount of time, it is either shorted high, open circuit, or it is too cold to respond (high impedance state). If the sensor is heated, the heater may have failed.
P0154 Rear Cylinder
If the sensor voltage does not come down to a normal operating range after a calibrated amount of time, it is either shorted high, open circuit, or it is too cold to respond (high impedance state). If the sensor is heated, the heater may have failed.
So those codes are telling you that you have the same issue front and rear cylinder. Did You put the complete stock exhaust back in place? If not I would start with that. I would also have the dealership check that the sensors ground is not faulty as that could be possible but not likely. This could be a connection issue at the ECM as well on the sensor ground wire side.