Full throttle probs with PHBH30

Hi People
Ok my T5 malossi 172 with PHBH30 has a problem at full throttle, it seems to lose revs thus slows down.
Its fine from the start and through all gears untill it reaches full throttle, and also when i thrash it from the start through all the gears on full throttle, needle x3, atomiser av260, needle valve 225, choke jet 70, idle 55, main 130.
I`m thinking it could be the main jet can anyone help.
cheers Andy.

Hi Dylan

I started it today and straight away found the pipe had b***n, fitted a new pipe (sito), checked the timing,A OK.Went for a blast, same problem at full throttle, also noticed that between half and 3/4 throttle it sounds like machine gun fire , does this mean that the slide needs to weakened off alittle? i`m not sure.
Anyway checked the plug after a blast it was blackened and wet to rich.
What main jet and slide adjustment would you recommend.
Dylan, thanks for your help in advance.