sounds like you change gears toooo fast, but stil i know wat u mean .... nothing wrong with your tuning, u have to shift your gears appropriately bcus of the cdi restriction between 5-6k rpm. unless u had ur cdi de-restricted... if you still wants to pickup fast and ur high gear still very good, change your spockets, play the with the spockets ratio around.. no gurantee for higher top speed.
btw anyone riding aprilias here had their piston block change to a different cc before?? 149cc, 154cc, 199cc? ...