what kind of currents voltages does a spark plug see in a small capacity single cylinder bike engine?
Thanks

typically 15 kV give or take a few K V.

google may give more accurate answer.

not sure about current, I would need to think about that but would say in order of milliamps.

i'd agree, if you assume the ignition system take about 1HP (no idea if thats ballpark?) I make that around 50 mA

A plug typically needs 12-15kv to actually initiate the arc, as soon as this happens voltage will drop down to a few hundred volts for the spark duration.

Peak spark current is surprisingly high, 200mA or more is quite possible from a modern system.

The power drawn by the ignition system is primarily related to primary current, a modern electronic system might have a maximum primary current of maybe 6 amps, so the absolute maximum power draw would be 70 watts in this case. However the coil never draws full primary current continuously so actual power will be lower, and will be proportional to RPM for an electronic constant energy system.