Is it all the power ? Or just a little. Is it standard ? My zip with a TT lost a little power when it was warm. It could be warn rings i'm not sure. Could just be general wear and tear.
not all power just abit, and no not standard it got a tecnigas exhaust,Polini variator kit and rollers,polini kelver belt
I would think its something to do with barrell, my speedshite 50 did it and a few months later my rings went.
It can be the problem. If it's running lean they can be down on power. 52 standard so like 62-65.... Try that and see if that fix's it. May want to check the bore for wear.