Uneven running

[XXIIStu 2]

I have a 2001 X11, the only "modification" is a pair of black widow end cans. It starts well, no unusual noises, and runs okay until I'm riding at a "neutral" throttle (neither accelerating or slowing) it has something like a misfire, but not a misfire, just runs unevenly, not jerking or banging. On acceleration it's fine, very satisfying in fact! Could it be the injectors? Is it even worth worrying about? MPG seems about right I think, getting around 150 miles between fuel lights. 

Any ideas????

[wayne 428]

If its a slight Hunting, (uneven sound) throbbing its normal, if you get 6 or more x11 together doing it they sound like Lancaster bombers