Why does my motorcycle top out at 75?

Messing with the carbs would not put air in your clutch, that was just coincidence. Ask the shops if they changed your jetting. If they did what from and what to. If not the process of syncing carbs involves hooking up vacuum gages and then adjusting your mixture screws. I've been in the bike game 11 years and have only met a couple people who can do this properly without a manual on hand to tell them how to set the carbs correctly. As the mixture usually only affects idle and throttle response, I'd be wondering if they put all the jets back in the right places. Outer carbs run cooler and thus need to be richer than inner carbs. Also are the secondary needle settings correct? These would be the most likely to affect top end perfromance uming nothing else was changed.