First things first. Let us distinguish the important differences in spark plugs threaded ends. They come in four diameters and lengths. They come in nominal 14, 10 12 and 18 millimeters diameters. Before there was a slight difference in thread configuration especially in different countries however, this was made uniform by the international standardization of the thread forms. These new dimensions are now being followed by motorcycle parts manufacturers.



Errors. People often make plug-reach errors. The very usual error is using 3/4-inch plugs in 1/2 –inch holes. The result of the same is pretty obnoxious. In time, when the plug threads are exposed in combustion, they become filled with deposits. In that case, it will be hard to remove the plug without removing the hole threads. On the contrary, if you use a short plug to a deep hole, the deposit will fill the hole and it will be hard to re-install the right size plug. The worst error is the use of overly-long plug. The exposed threads absorb huge amount of heat from the combustion process which alleviates the plug-nose temperatures. As a consequence, the side electrode functions as a glow plug. Early ignition or runaway pre-ignition causes higher combustion chamber temperatures that can wreck the engine.

Heat range. Hot plugs are plugs with a long insular nose. They lead heat high into the plug body before it returns to the cylinder head. Short-nosed plugs, on the other hand, have shorter heat path. Consulting the spark plug manufacturers regarding the plug’s heat range can be of great help. This may somehow clear the cobwebs at the back of your mind regarding heat range demands. Knowing which plugs are colder or hotter may be easy if you stick to the same brand however, it becomes perplexing when you change from one brand to another.

There is more to spark plugs than the three aforementioned aspects. There are still areas that we need to master like its installations, different plug configurations and maintenance work. Nonetheless, we have to be first acquainted with these three aspects.

In a nutshell, we have to have enough knowledge about spark plugs in order to choose the right or suitable type. Another, we have to delve deeper to what it has to do about the bike engine’s condition. These factors are hard to acquire and do, thus, we have to instill a lot of details and facts all at once. When you get it right, you will be favorably affected.