I have fuel gauge with wideband. Wur mod is done. Engine goes lean 16:1,17:1 after 6000rpm. Its light ported 6a, abf cams. Is this normal air/fuel ratio with k-jet? If I want best perfomance midrange idle air/fuel ratio is 10:1, midrange 12-14 a/f. If I ser idle 13, it's lean everywhere.