help bike missing on 1/4 throttle only

[dveale]

hi guys first post looking for some help have a 00 zxr 400 bike ticks over no problem and if you drive it on full throttle it runs perfect but at about 1/4 throttle its missing on what seems to be 1 or 2 cylinders hard to tell. it misses on 1/4 throttle on all revs tho no matter how fast or slow you go. rebuilt the carbs new idle jets new mains new fuel adjusters. diaphragms look good new plugs and coils inlets look good aswell. just wondering did anyone have a similar issue have been looking checked all the similar issues in forum cant figure it out? also the engine was checked out when the shims were done about 4 months ago had the same issue then aswell. any help help welcome thanks