Fitting bigger spark plugs might sound like a recipe for improving power output, but it can have catastrophic consequences ...

Read a good spark plug lately? We hope so, for your engine's sake. But spark plug reading—the traditional way to check your fuel mixture and monitor other vital conditions in the combustion chamber ...

If you consider your spark plugs little more than disposable engine parts to be replaced for every event or two, you're missing out on a valuable engine-tuning tool. Not only can the correct plug ...

Harley-Davidson’s Milwaukee-Eight engine carries four spark plugs across just two cylinders, a setup that strikes many riders ...