Granted, I've no experience with a Zuma 125, much less a kitted one. Not been able to find hp ratings for one either but the motor is the same bore and stroke and the Agility but with only 10:1 compression to the Kymco's 11:1 which is rated at 9.25 hp. I'm guessing it would take almost 15 hp to go 65mph. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.