Hesitation?

[nickodemon]

That was exactly the thing i was going to suggest if the bike was fully warmed up. If it was still cold standard fazers can slightly foul the plugs when cold, but if fully warmed up the fuel filter is very likely. i had a fazer 600 that used to hesitate when i snapped the throttle open. On inspection of the fuel filter it looked dirty, so i replaced it and it made a massive difference and completely got rid of the hesitation   A pattern fuel filter will be fine.