50’s scooter drives faster than before after a visit to the workshop

Hello together, I’ve already read a lot here, was registered once and now again. I brought my Suzuki Estilete UF50 to the workshop a week ago, because it ran with normal carburettor setting (air screw 2 1/4 revolutions back) lean and went out with fast full-gas-giving. I wanted to have an inspection and new tires, because the old one was still mature and I had a nail in the back. I brought the scooter yesterday The boss said they had cleaned and enlarged the main nozzle a bit, it was changed brake fluid and transmission oil. Further the vario-rolls were replaced and a new V-belt was inserted. It is now also running great, but it reaches according to cell phone gps measurement 61km/h ???. Formerly the carburettor replica was run to the 56. Then I had bought at that time an original carburettor from Suzuki and according to gps it did not run faster than 53… wanted to have everything original. I am he and the head of the workshop said that it would have run so slowly because the belt was completely worn out. He offered to install a throttle so that it would drive about 5km/h slower. You couldn’t set it up like a clock. My question: if it had run too thin before, because it would have pulled the wrong air and enlarged the nozzle. Would this explain the increase in performance? I mean, that’s not fuss to enlarge the nozzle with ne r Reibahle? I play with the idea of using a lawyer, but technically I’m really not on the line with scooters. Can you understand where an increase in the maximum speed can come from based on the work that has been done? Can it be that they have forgotten to install the original chokes? Do I need special tools to check this? I thank you now for your expert feedback. I don’t really want to cash in. The machine should already correspond to the original type approval. Greetings Nefle