Red Seal Motorcycle Technician Practice Exam

How does a cush drive function in a motorcycle?

1. It increases the horsepower delivered to the rear wheel

2. It dampens engine vibrations and shock loads sent to the rear wheel from the chain

3. It improves tire grip on the road surface

4. It serves as a suspension mechanism for the rear wheel

The correct answer is: It dampens engine vibrations and shock loads sent to the rear wheel from the chain

A cush drive functions primarily to dampen engine vibrations and absorb shock loads transmitted to the rear wheel from the chain during acceleration and deceleration. This system uses rubber or elastomeric components which are designed to flex and compress, thereby reducing the impact of engine pulses on the final drive and improving the overall ride quality. When a motorcycle accelerates or decelerates rapidly, the sudden change in torque can lead to harsh vibrations and shocks that can affect both the mechanical components of the motorcycle and the rider's comfort. The cush drive mitigates these effects by allowing for a degree of movement between the rear wheel and the drive system, which smooths out any abrupt transmission of power and helps preserve the integrity of the drivetrain. In contrast, options suggesting that it increases horsepower or improves tire grip do not accurately reflect its function. While a cush drive can contribute to better handling and stability indirectly by reducing harshness, its primary role is not related to grip on road surfaces or power delivery in a direct sense. Similarly, describing it as a suspension mechanism does not capture its specific purpose, as cush drives are distinct from the suspension systems designed to absorb bumps and irregularities in the road.