Amotorcycle with mass 100kg can accelerate from 0-60mph (0-26.8m/s) in 2.8s. what is the force of the motor and what is the power if this acceleration can occur in 37.52m?

WE cannot know the force ( torque) of the motor. 
We can know the force at the rear wheel. 
F = ma = mv/t 
= 100 * 26.8 / 2.8 N 

There is a problem with the second part. Constant power would require an infinite force at speed zero. 
If you take constant Force then the power requirement increases with increasing speed. 
Which one do you want? 

Constant force means the MAXIMUM power is 
F v = 100 * 26.8 / 2.8 * 26.8 

Iwould choose the same momentum because if they throw a baseball very light and not hard at all then doing it with a bowling ball won’t hurt that worse