Spark Plugs

Everyone knows what a spark plug does. But many questions are asked about why certain attributes of the spark plug exist. Here is a spark plug FAQ that answers these questions.

The ability to read spark plugs can tell your or your mechanic a lot about the state of tune of an engine and about some of the problems an engine may be experiencing. In the absence of other more sophisticated equipment, the simple act of removing the spark plugs and examining them under a low power magnifying glass can help jet the carburetor, set ignition advance, recognize additives in fuel and many other conditions. While no one can learn to read spark plugs by simply studying a short article like this, you can learn the basics. We have provided two guides to reading spark plugs. The first guide provides information provided by the spark plug manufacturer, the second guide was created by an experienced motorcycle tuner. Reading both will provide you with insight into the art of reading plugs.

When you need to make serious horsepower, sometimes you need to make adjustments to the spark plugs. Indexing the plugs and adjusting the plug gap can add a few extra horsepower to your engine. Here is some additional information on getting that last little bit of power from your engine.

V-Twin Café provides a spark plug application and interchange chart for Harley-Davidson motorcycles, including 80 CID Evolution engines, Shovelhead engines and all Sportster engines