Aerox ns50 bogging down mid speed

Hi, just joined this forum and gonna ask some questions. just fitted a yasuni z pipe which gives great performance from 0-15 and 25-40 but it falls out of the powerband from 15-25. gets better when the engines warm, so i believe its running lean? so i think i have to move the clip on the needle down right?

gonna fit a foam air filter and bigger main jets while im at it, i bought a 75-92 gurtner main jet set are they the right ones for the stock carb?

never done anything with tuning i only fitted the new pipe but i watched a good video let me know if im on the right track

 

also its just a stock derestricted aerox

 

Sounds like you are on the right track