The 1990 Suzuki RGV250 Ignition System consists of the following parts: Generator, CDI Unit, Ignition Coil, Spark Plug, Battery, and Switches. The ignition system operation is such as follows: There is a DC-DC converter in the CDI unit, which steps up the battery voltage to a higher voltage and charges the capacitor (C). An SCR connected to the capacitor becomes conductive (turns on) when a forward voltage signal is sent to its gate allowing the electric energy stored in the capacitor to discharge instantly to the ignition primarily coil. This then causes a high voltage to be induced in the secondary coil and a hot spark jumps across the spark plug gap.
Therefore, the spark in the spark plug occurs when the SCR is turned on. In other words, the SCR’s being turned on is the ignition timing (or spark timing). This ignition timing is controlled by the control circuit which process the signal generator pulses to form an SCR gate signal. The signal is then sent to the SCR just when the crankshaft has reached the best ignition timing for the current engine revolution.