If My EMMO Zone Se - bike only goes 50 kph at top speed. What changes can I make to get 90 kph?

emmo.ca/faq
"Legal travel top speed is 32km/h. Off-Road top speed can reach up to 65km/h base on the model."

You only have a 500 watt motor, about 2/3 horsepower. Even a small gas powered bike has 20 times that.