Angular momentum; flying motorcycle

[MrRice5555]

Homework Statement

The distance between the centers of the wheels of a motorcycle is 155 cm. The center of mass of the motorcycle, including the biker, is 88.0 cm above the ground and halfway between the wheels. Assume the mass of each wheel is small compared with the body of the motorcycle. The engine drives the rear wheel only. What horizontal acceleration of the motorcycle will make the front wheel rise off the ground?

Homework Equations

$$\Sigma$$ $$\tau$$= I $$\alpha$$
$$\tau$$ = r x F

The Attempt at a Solution

I don't know how to even start this. I drew a diagram, and tried to sum the torques by placing the axis of rotation at the center of the rear wheel. Have no idea what to do from there.

 

[gneill]

Try putting your center of rotation at the point where the rear wheel touches the ground. What are the forces acting on the center of gravity?

 

[MrRice5555]

OH I see there's a force applied from the engine as well as the weight of the engine. I believe I got the answer. Thanks!