Red Seal Motorcycle Technician Practice Exam

When should the spark plug in a motorcycle be replaced?

1. Every 1,000 km

2. As recommended by the manufacturer, typically every 6,000 to 10,000 km

3. Once a year

4. Only when it fails

The correct answer is: As recommended by the manufacturer, typically every 6,000 to 10,000 km

The optimal interval for replacing a motorcycle's spark plug is as specified by the manufacturer, which usually ranges from every 6,000 to 10,000 kilometers. This recommendation is based on the design and materials used in the spark plug, as well as the operating conditions of the motorcycle. Regular replacement at the manufacturer's guidelines ensures optimal engine performance, fuel efficiency, and reliable starting. Spark plugs can wear out over time due to factors such as combustion deposits, erosion of the electrode, and thermal cycling, which affects ignition performance. By adhering to the manufacturer's recommendations, riders can ensure that their engines function smoothly and efficiently without the risk of misfiring or starting issues. While some believe that spark plugs can be replaced based on distance or time alone, following the manufacturer's guidelines takes into account various performance factors that influence the lifespan of the component. This approach is crucial for maintaining the overall health of the motorcycle's engine.