Those carbs are certainly not K0: they look like mid-year 1975, the 086a variety from the 750F0/1 bikes. If that is so, they probably have the #2713101 Or similar) needles in the slides, which can make the engines with K0 cams feel 'flat' between 2000-3500 RPM or so. The later cams opened at 0 degrees BTC intake, so they are set leaner. You can try lifting the needles to the bottom notch to work around that, and make the mainjets #110 with the air screws about 3/4-7/8 turn out (instead of 1 turn) to blend in the earlier-opening cam's performance. Alternately, you could install the standard #27201 needles (if you can find them!), avaoid the rebuild kits' brass parts today. They are ALL incorrect, and run very, very lean, making the engine feel very weak.