What is the maximum sustained horizontal acceleration possible on a flat track in a motorcycle whose wheels are 2 m apart centre to centre, centre of mass symmetrically between the wheels and 0.5 m from the ground? assume friction with the road is not limiting.

To determine the reaction on the front wheel, we do a momentum balance on the rear wheel aligned with the center of mass:
W(1) = W(0.5)(1) + R(0.5) 
R = W

For the motorcycle to accelerate, there must imbalance of forces, so:
ma = R - F
since friction is not limiting:
ma = mg(1 - 0.5)
a = 0.5 g

Therefore, the acceleration is 0.5 g or 0.5(9.81) = 4.91 m/s2