Issues with 2nd cylinder on 2011 and 2013 bogging

Hello. I am having an issue with both my 2011 and 2013 gv250s. Both idle and sound great but once I start riding the second cylinder starts to sound like it’s boggling. There is a sweet spot around 75% throttle where both cylinders on both the Motos run perfectly but once at full throttle the cylinder starts to bog again.

I have replaced ecu’s, injectors, plugs, coils, even on the 2011 even the wiring harness but cannot solve this issue. Can someone help me out?

Thank you!