Piaggio Zip 70cc 2T rev loss

so pretty much as the tittle says, doing about 30ish half throttle then give it full throttle and the revs just disappear, and the bike just rolls like its in neutral or something, the engien dont cut out. i raise the throttle up and is back. so its like 3/4 throttle it cuts out? any ideas, advice?

Im running
pmtunning 70cc bore kit
premix
and recently changed the whole variator kit, including the rollers to 6.5/7.5g 19x15.5mm rollers
(before you mention the rollers, it had different ones before but still did the same)

 

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