I got a '08 Streetmate R 50cc with some mild porting and shortened Bullet. Still got the stock airbox. I'm hitting 50mph (cyclometer and GPS) on the flats, full tuck. Oh yeah, 26x24 gearing too!!! I got out to 54 with 26x22!
The A55 still has much more potential to be tapped. I wonder if I with bigger carb, more radical timing I can get to 60/50 club! HA!