Have the same sound on my Agility City 125 from about 38mph up. Really annoying... The sound started after I changed the belt, rollers and clutch.
I'm 99% sure it's coming from the CVT.
When the scooter is cold nothing can be heard, but as soon as it warms up the whoa - whoa - whoa starts.
Checked and tightened all the bolts on the muffler, and center stand, but no change.
. Still have the old belt in the garage, and it's in fairly good shape, so gonna put it back in and see what happens.