How Often Should Motorcycle Spark Plugs Be Replaced?
2 Answers
Motorcycle spark plugs should be replaced every 20,000 kilometers. The replacement method is as follows: 1. Remove the engine cover and unscrew the fixing screw of the high-voltage wire terminal; 2. Remove the high-voltage wire terminal, loosen the spark plug, insert the hose on the high-voltage wire terminal into the combustion chamber, and pull out the spark plug; 3. Align the new spark plug with the screw hole and tighten it with a tool. The working principle of the spark plug is: to ignite the mixed gas in the cylinder through the arc generated by the voltage between the electrodes, maintaining the normal operation of the engine. The function of the spark plug is: to discharge the pulse high voltage sent by the high-voltage wire, break down the air between the two electrodes of the spark plug, and generate an electric spark to ignite the mixed gas in the cylinder.
I usually commute by motorcycle and enjoy short trips, so changing spark plugs is something I pay special attention to. Standard nickel alloy spark plugs typically need replacement every 15,000 to 20,000 kilometers, while iridium or platinum ones can last up to 30,000 kilometers. But don’t just memorize these numbers—the key is to monitor your bike’s actual condition. I make it a habit to check the electrode gap after every wash, using the thickness of a bank card as a reference. If the gap exceeds 0.9mm, it’s time to be cautious. If you notice delayed ignition or engine stuttering during acceleration after riding in high summer temperatures, there’s an 80% chance it’s a spark plug issue. Once, during a high-altitude trip, I delayed replacing them and ended up struggling with cold starts until I switched to NGK iridium plugs. Pro tip: riders who frequently take long trips or prefer high-RPM riding should replace spark plugs 20% earlier than the recommended mileage.
