Attaching a jet pack always made mine go faster...although they are hard to find at a good price.
Alternate Ideas would be:
but a engine in it
the brake
An improved flow of air and fuel mix will make the scooter faster. You can do this with an aftermarket exhaust.
Go downhill
== ==
Loosen the headset a bit.
Yes it will make the scooter go faster, but you could run the chance of blowing parts in the moter if you do so
push it off a cliff
get a gas powered one
Really nothing get a 150cc
Unlock the gas on the handlebars
lose some weight