Hmm, what year is it? I have a 2005 with 72cc naraku piston, runs out the tacho (80km'h\50mph). I have cut the cdi, new variator with 5.5grams rollers, a 1500rpm centerspring and "lvl1" clutch springs at the moment.
A new cdi or cutting the original one (depending on year) is the key to get some more power (rpm).