An accurate bike sim that is fun to play is going to be a very steep challenge. I recommend abstracting the idea and making something arcade-style in design, but with realistic performance. Otherwise, it will be very difficult to prevent the bike from being erratic and difficult to control.
Which kind of implementation you use depends on how you want the bike to feel. Maybe a rolling sphere 🙂:
https://kidscancode.org/godot_recipes/3.x/3d/3d_sphere_car/