I adjusted my starter valves last weekend and I noticed cylinder 1 had alot of variation in vacuum level but #2, 3 and 4 were fairly steady. The vacuum level of # 1 would vary fairly quickly about by about 30 mm.. #2 would fluctuate very slowly kind of following the general trend of #1. 3 and 4 were very steady although very sensitive to adjust with very small adjustment of the screws. Have others seen this? Yah, I'm old school with mercury manometer. back from my carb adjustment days which I am soon to return to this winter when I resurrect my 86 VFR750.
be sure to snap the throttle between screw adjustments so the new setting can settle into place and overcome stiction in the linkages.