Quote from: MotorGeek on January 09, 2016, 04:53:11 pm

1.  Check the peak voltage at the feed wire terminal on the ignition coil where the wire from the CDI is connected.  (The wire from the CDI must be connected to the coil during this test.) The voltage should be at least 100 volts.  If the coil is good it will spark with 60 to 80 volts,  but not usually run good under a load.    If it is over 100 volts and do not have spark, replace the coil, or plug cap or spark plug wire. 

With the below mentioned "oscilloscope or a digital voltmeter/multimeter with peak voltage capability" the motor DOES or DOES NOT need to be turning over (kicking it) during the test mentioned above?

Quote from: MotorGeek on January 09, 2016, 04:53:11 pm

To measure peak voltage you need an oscilloscope or a digital voltmeter/multimeter with peak voltage capability or a peak voltage adapter that plugs into your voltmeter/multimeter.

If you do not have a peak voltage adapter you can make one for about $2.00.  Google how to make a peak voltage adapter. 

Thanks

The engine has to be turning over at least at cranking speed to conduct the above test.  Most dirt bike CDI ignitions need to turn over 400 to 600 RPM to generate enough peak voltage from the stator to charge the capacitor and then trigger the capacitor to release the voltage to the ignition coil. 

The test measuring peak voltage simulates what is actually happening when cranking it over to start.  Most CID ignitions need to about 100 volts sent to the coil to make enough spark to start.  When the engine is running the voltage sent to the coil goes up.  Some CDI ignitions will send over  200 volts to the coil at medium to high RPM. 

If the coil has a turn ratio of 200 : 1, the spark plug will receive approximately 200 x the input voltage or 100 volts x 200 = 20,000 volts

The pulser or trigger coil needs a pulse of 1 volt or more sent to the CDI to throw the switch that allows the capacitor to discharge the 100 volts or so  that it had been storing.