scooter wont go faster than 50mph

Hi i have a 2007 125cc tgb 204 classic 4t it will not go any faster than 50mph i know someone who has a stock 204 that touch's 60-70mph why wont mine go any quicker it was stood for a year recently stripped the carb cleaned it emptied fuel tank cleaned fuel tap fresh petrol in her and sorted it out and got it to pass its mot any help or further info needed let me know

 

have you tried different rollers or maybe an after market exhaust ?

 

I have checked the rollers they are fine new stock weights and the exhaust is good i don't want to replace good parts to get speed i know the bike is capable of it has an inline fuel filter between the tap and the carb could this be restricting fuel at higher speeds

 

Doubt it, if it wasnt letting enough fuel thru you'd feel the bike "cutting off"