With a single speed instead of a CVT you can gear it for take off or top end . Unsure if you could swap out the chain drive for CVT components .
I had many pedal mopeds that were slow on take off and uphill since they were single speed chain drives . I also had 3 Tomos Bullets that had a 2 speed tranny like a Chevy Powerglide which was a huge improvement . Maybe the guys at
www.mopedarmy.com could tell you if you could use the Tomos tranny as I have not wrenched a Geely engine before . Here is some parts including a BBK that should have more power
http://www.scrappydogscooters.com/Ge..._2T_parts.html