Yamaha Genuine Spark Plugs

Characteristics

Heat Range

When fuel is burned imperfectly inside the combustion chamber, carbon is formed as a result. Spark plug misfires and smoldering (burning without fire) result when this carbon sticks to the spark plug. These carbon deposits will burn off of the spark plug within a fixed temperature range, but if the spark plug's temperature is too hot, then pre-ignition, reduced engine output and piston seizure can occur.

In order to keep the engine running at top condition, and prevent the above mentioned troubles from occurring, each spark plug functions within a recommended operating temperature range. This temperature range is known as the "heat range"

Spark Plug Lifespan

Because the spark plug is a consumable part, even when properly used, it requires periodic replacement. Spark plugs that have been used for a long time and that are degrading in quality will have difficulty in sparking, cause pre-ignition and cause engine trouble. This will in turn bring about reduced fuel economy.

Cutaway

A good mechanic first checks the spark plugs to see how they are burned