Slides are vacuum controlled... butterflies are operated by the cables. All should work identical (for the most part) between carbs. If one of the slides are lagging, it could be hanging up or a vacuum leak or a pin hole in a diaphram or some other small issue could cause that.
Also carb sync could be at the root of the problem.
08 KTM 950 SE, 09 KTM 950 SE, 04 KTM 950 ADV, 10 Husaberg FE390, 66 Kawasaki B8S Super 150
Hi/low beam conversions for: Trail Tech
, Baja Designs