Contrary to what the CPU will do, you do not need to jump over the bar at all. You just need to reach its height level. To do this, rather than trying to jump over the bar and risk knocking it off, jump using the other two sides of the ramp and just air up next to it. You will know when you have reached the required height when you see your score appear at the top of the screen. All you have to do now is stick the landing.