Wouldn’t that effect the engine at all rpms? I also took air box off and felt inlet of carbs and all seem to have vacuum so I don’t think it’s the reed valves. I did notice how wet and saturated the inlets were with gas. Also the air box was heavily coated in gas/grime
I posted videos to show. One at idle and one revving in neutral. Coughs and shakes intermittently at idle, stalls in and out of gear only at idle. Runs flawless above roughly 2k to WOT. S/N 1B003807