My 2007 sabre 1100 has just the same issue. Runs great till just under 4000rpm then starts missing badly. It is bad in 1st and second. Changing up a gear reduces rpm and fixes it till 4000rpm is reached again. I've changed plugs, leads and cleaned out and balanced carbs etc to no avail. Also changed fuel filter and checked fuel pump. I'm a bit baffled by the issue. I still ride the bike but if anyone has any ideas about what to check out next I'd like to hear them.