Lean idle. Rich cruise.

I revived this post as I'm having a similar problem. running an XP850 and perfect at idle, perfect at WOT, but pig rich at cruise. Like 11 to 1 ish. Light 4 speed car with 4:30 gears. Timing locked at 33 degrees.

Tried changing air bleeds, P Valves....all for naught. Jetted primary from 84 to 77 and cruise was fine but any "spirited" acceleration on just the primary got dangerously lean.

So carb is now back to box stock config, hoping to fin a fix for my issue. Wondering why the PO blocked the middle emulsion? I'm carb stupid when it involves anything other than a jet change.