Welcome Kymco Owners!
My owners manual says the tank holds 3.3 gallons. I refill on empty every time look at my fuelly numbers. 2.2 gallons, 2.35 gallons never 3.3 gallons.
Your tank would have to be dead dry to put in 3.38 gallons. Also, I'm a guy! I chose sissy mary as a joke because I ride a scooter.