Lets see a pic of the ass of the bike. (dropouts)
Was the original motor a 10mm axle flat? Bike std vs. scooter std.
Whats the matter with the OG motor? 500w is just a number, your 12fet Lyen is good for 6x that @ least.
I'm sure a Gio motor is good for 50+kph @ 1500w ish & bursts of more.
Want to go faster? Dump the saggy lead. That alone will give you a major boost.
18s lipo or 20s life4po will shock you in comparison.
16s a123 26650 transformed this "500w" Scoot.
500w Gio's are a dime a dozen where I live. Where are you located?
I think you can find replacements motors @ various sources/dealers throughout the GTA.
If you want something better you are going to have to pay(for a new motor capable of more) & show a pic of your dropouts.
For a better recommendation.
HK lipo packs. 18s?p