Each spark plug cap (or spark plug socket) has a type designation, made up of letters and numbers. Usually the correct type designation or code can be found in your motorcycle's workshop manual or instruction manual. This code is a logically structured formula containing important information about the spark plug and the spark plug cap. Crack the code? You can do it easily using the table below.
Spark plug cap angle
This letter refers to the shape of the spark plug cap and the angle in degrees. For example, on some engines an angled spark plug cap is needed because there is not enough room for a straight one, on some engines a longer spark plug cap is needed.
Diameter of the ceramic insulator of the spark plug
This letter refers to the maximum diameter of the ceramic insulator - the "white part" - of the spark plug. Spark plugs vary in diameter, so it is important that the spark plug cap is wide enough to fit over the spark plug.
These two figures refer to the resistance value of the spark plug cap. This value is always model specific and is specified by the manufacturer of your motorcycle. Consult the workshop manual or your motorcycle's owner's manual.
Spark plug power connection
This letter refers to the top of the spark plug, which is either an SAE connection or an M4 thread. The power connection provides the power transfer between the spark plug and the spark plug cap. It is therefore important that the connections match.