Speedfight New Exhaust Bogs

Hello, so recently I had to buy a new exhaust for my speedfight 3 50cc LC (2011). Not knowing much about moped/bikes etc I bought a Q tre sports exhaust thinking the bike would run the same if not better. (I was going around 45 on a flat - and now I go around 35) but no the bike got slower in every way. I then read up and realised I had to upjet the carb which I did but about 10% and this didn’t change anything. Just wondering what else there is to do that could make me go faster again.
Cheers

 

when you fit a sports exhaust, it moves the power band further up the rev range and you pretty much always need to fit lighter rollers.