[Gaz64]

While your A/F ratio is near correct at 3000 and 6000, no main jet or high speed air bleed change will cure your heavy richness at 4100.

If you have a think about leaning the main system by either a smaller main or larger air bleed to make 4100 rpm correct, the rest of the band will go lean.

Your metering block would also have replaceable emulsion bleeds (most probably the issue here) which Pro-systems should be able to address for you.