The dirt bike Spark cap manufacturer tells you that the spark plug cap can improve the damping effect of the engine ignition system on the current, thereby weakening the ablation of the spark plug electrode, more effectively suppressing and attenuating the electromagnetic wave interference of the engine ignition system to the radio equipment, prolonging the use of life.

This resistor has two functions, the first is impedance matching. The manufacturer of dirt bike Spark cap tells you that because the impedance of the signal source is very low and the impedance does not match the signal line, after a resistor is connected in series, the matching situation can be improved to reduce reflection and avoid oscillation.
The second is to reduce the steepness of the signal edge, thereby reducing high-frequency noise and overshoot. The dirt bike Spark cap manufacturer tells you that because of the series resistance, an RC circuit is formed with the distributed capacitance of the signal line and the input capacitance of the load, which will reduce the steepness of the signal edge. As we all know, if the edge of a signal is very steep and contains a lot of high-frequency components, it will radiate interference, and it is also prone to overshoot.
Typically, such resistors are only considered in high-speed signal lines. The manufacturer of the dirt bike Spark cap tells you that in the case of low frequency, it is generally connected directly.