What would be the typical symptoms (engine performance-wise) of a weak spark on a 2-stroke, say a CR125? Or, does the spark really matter if the engine seems to crank easy and run quite well? Likewise, are their performance advantages/disadvantages to having a stronger spark than normal? NOTE: I'm an electronics engineering instructor and the electrical part of the engine is no problem for me (other than how that spark really relates to the engine side of things). I do find it a disappointment there are no voltage measurements noted in the service manual, only static resistance measurements. Resistance measurements sometimes don't reveal electrical problems, especially when high voltages are involved. I do have equipment that will allow me to measure voltages (even pulses and spikes) up to 50kV and feel--if this info was available--could make actual meaningful measurements while an engine was running. But, I do understand that most probably don't. Still, even most could measure voltages around the CDI and before the coil, I would hope.