Bodeen,
I've got about 1200mi on the 21's now and have experienced this also. Exactly like what you've described or combo miss/flat spot sound/feel. Maybe at the right rpm & load this is just what these cams do and traveler hit the nail on the head here in post #2..??
I don't have any problem rolling on the throttle from that point nor is there any flat spot rolling on from any point.
BTW I'm EFI.....
Also,this also doesn't happen all the time, just once in awhile. Maybe when the bike isn't fully warmed up (not exactly sure).
Mine does it cold and hot and I can make it happen on demand. It doesn't feel flat or dead to me its a sound that isnt pleasing......
It rolls on from any spot very well. What exhaust do you have?