In addition, her bicycle is not aerodynamic and likely weighs between 20-30 lbs, whereas a race a race motorcycle is very aerodynamic and might weigh between 40

In addition, her bicycle is not aerodynamic and likely weighs between 20-30 lbs, whereas a race a race motorcycle is very aerodynamic and might weigh between 400-500 lbs. I'm sure the rolling weight of the wheels would dramatically impact stability as well.