Thank you for your answer. Actually, I already have alternative solutions to reduce the value of fCGHeight or the height of the center of the bike from the ground, in
meters around 0.10. It makes the motorbike not be wheelie anymore. But when it is played at start, the vehicle looks like there is a jerking down motion. And when replay the race video, the vehicle's wheel half goes into the road ... haha. I don't know what file to edit fCGHeight.
If I increase the mass of the vehicle, it will reduce vehicle acceleration. And I tried to make the gear ratio as real as possible.