Which of the following is essential before riding to prevent engine problems?

Before riding a motorcycle, ensuring there is enough oil is essential to prevent engine problems because oil plays a critical role in lubricating the engine components. A well-lubricated engine operates smoothly, which helps to reduce friction and wear on the moving parts. Insufficient oil can lead to increased engine temperature, poor performance, and ultimately catastrophic engine failure if the engine runs dry. Regularly checking and maintaining the correct oil level is vital for the long-term health and performance of the motorcycle's engine, which is why it is prioritized before starting any ride.

Other aspects, such as checking tire pressure and inspecting brake lights, while important for safety, primarily address different operational functionalities rather than engine performance directly. Cleaning the motorcycle is essential for maintenance and aesthetics but doesn't directly impact engine operation in the same way that oil does. Thus, focusing on the oil level is crucial for preventing serious engine issues while riding.