Hi Frank ....Haven't heard from you for a while! If I recall you have a 2110 with "panchito" heads and a few other "tweaks" that Pat uses. This could be the difference.
Question...Is your flat spot a flat spot thru certain rpm range ? Or is it a hesitation when you start to push on the pedal ? I know you know some things about carbs so whats your guess ? Yes these Webers have adjustable accelerator pumps for duration of fuel injected and the nozzles can be changed too........Bruce