Scorpion not pulling into wind or up hill

Hi there i have T5 with malossi kit cosa clutch standard carb i have just fitted scorpion pipe i have gone up on main jet from 122 to 125 used scooter with new pipe for first time on friday pulls well from 1st to 3rd ok in 4th top speed is a lot better than with simonini but if strong wind can only get about 50 mph in 4th just will not pull have to change down to 3rd to get revs up again then it pulls ok .top speed so far abut 78mph not tryed 122 main jet would this help any ideas thanks Gary ps simonini would pull ok in to the wind with scorpion it seems how the bike used to be with out the kit on into wind or up a hill thanks Gary[:dance3:] [:smile:]

Gary, i have a mate who had exactly the same trouble, after alot of fannying about we changed the cosa clutch back for the standard and now it goes like a rocket.
I have a TS1 225 lambretta and he can keep up with me at 80mph, i was well impressed! (then i left him…lol);D