Air Screw settings with K&N filter fitted


Apr 6, 2014
My '99 750 has an Art end can and a K&N Filter fitted. When I bought it it was running eyewateringly rich at idle (no exageration it genuinely made my eyes stream) checking the air screws on the throttle bodies found them to be significantly out from standard settings so I reset them to standard. That did cure the idle richness and the temperatures remain at a steady 76 on the move but it's begun to bother me that maybe it should have been left slightly richer. Obviously a full dyno and mixture set up would be the best bet but in the short term does anyone have any idea about the following
  1. Does the air screw just affect idle or does it influence fuelling throughout the rev range
  2. Anyone have any suggested settings for the set up described above?
Any input gratefully received, Thanks