Red Seal Motorcycle Technician Practice Exam

How does the throttle affect the motorcycle's performance?

1. It acts primarily as a braking mechanism

2. It controls the air-fuel mixture entering the engine

3. It adjusts the tire pressure

4. It changes the brake sensitivity

The correct answer is: It controls the air-fuel mixture entering the engine

The throttle plays a crucial role in the motorcycle's performance by controlling the air-fuel mixture that enters the engine. When the rider twists the throttle, it opens the throttle plate in the carburetor or fuel injection system, allowing more air to flow into the engine. This increase in air intake necessitates a corresponding increase in fuel to maintain the optimal air-fuel ratio for combustion. By adjusting the amount of air and fuel that enters the combustion chamber, the throttle directly influences engine power output, acceleration, and overall performance. When more air-fuel mixture is permitted into the engine, it can produce more power, allowing for faster acceleration and greater speed. Conversely, reducing the throttle limits the airflow and fuel mix, resulting in a decrease in engine power. Understanding this mechanism is essential for maintaining and tuning a motorcycle, as it directly affects the rideability and performance characteristics of the vehicle.