There are still things to look at, Paul. Have you checked the fuel flow rate from the needle-and-seat with the float bowl plug removed? That checks the whole system upstream of the needle-and-seat. It should continue to flow a good stream, steadily: run the test for at least half a minute.
If that is OK, check the float height, idle mixture screw setting, and main jet size.
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2014/12/full-2772-19202-honda_gxv390_carburetor_settings.jpg)
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2014/12/full-2772-19203-honda_gxv390_carburetor_settings2.jpg)
Does it idle best with the screw set where it should be?
Does the float mechanism operate smoothly with no binding?