Free Performance Upgrades?

[NickDH]

Hi!
I own a 2008 Roketa Maui and was curious, what other free performance mods can I do on it, other than of course moving the washer on the diaphgram needle? (done already, improved acceleration a LOT)
I don't think my scooter is restricted, and if it is, it's in the CDI box.
I don't have much money to spare for the mods, as I've had several broken parts (tire cut through the brake line, front brake no longer works) and have already spent my money on those parts.
Is there anything else I can adjust that wouldn't put too much stress on the engine?
Thanks!!!