Re: Where to attach Tacho?
Tachometers are generally capacitor coupled so there is little danger of destroying either the ignition or the tachometer. The question is whether or not the tachometer can recognize the pulses it is seeing. As for the setting, a 2 stroke engine fires each cylinder every revolution of the engine whereas a four stroke fires each cylinder every other revolution. Since your tach will be connected to the primary terminal on a coil for just one cyliinder (each has its own coil) the tach will see one pulse per rev whereas on a four cylinder auto engine it would see two since there is only one coil). Therefore, on the 4 cylinder setting, you would need to double the reading.