If you feel that the handlebar of your Halfbike tends to keep to one side while riding on a flat surface then you probably need a tune up. You can easily fix this problem if you follow the steps in the video below. This will attribute to a far better Halfbike experience.
Note that this tutorial only concerns a handlebar that keeps off-center while you ride on flat ground. The Halfbike is sensitive to cross slopes. So it's normal if the handlebar is not perfectly centered if you ride on banked road or other tilted surfaces.