depends on what youve got on the bike etc for example mine is a 50cc sports kit, MK racing exhaust and a standard airbox, and a derestricted variator Top speed = 64 mph on the flat. Not to bad for a piaggio nrg power dt 49cc AIR COOLED
whats that got to do with it he is asking how to change the jets in his carb, and test that he has got the right size. there are good guides online, on mopedarmy etc, actually changing the jet is easy it just unscrews if you remove the bowl you will see the jet and can unscrew it, do plug chops to determine whether you are rich or lean
its got everything to do with it because Hes asking how to jet a carb - in other words setting it up correctly. Maybe i read it wrong but to me thats what it seems like so thats y i said is it a 50cc or a 70 purely because if its a 70cc he would need bigger jets. Also you take the float bowl of the bottom of it and unscrew the main jet, I can upload pics of mine to show you how. Anyway i dont like giving advice like what jet he should be running without me knowing whats on the bike
On a carb you have the main jet and the pilot jet, The Pilot jet is for when the bike Idiles and the main jet works when the throttle is pulled back. 99% of the time you dont need to change the pilot jet and only the main jet. Unscrew the float bowl ( bottom of carb) allow the fuel to drip out and change the main jet which is the bigger one. The size of the jet will vary depending on what your upgrading on the bike