Motorcycle Repair: No Spark, wiring schematics, ac volts

Question
I have a1994 Suzuki DR125SE 4 Stroke.I'm not getting any spark the bike has 3499 miles on it.  HHHH EEE LLL PPP !!!!!!!!!!

Answer
Jim, most of these small bore bikes have a CDI ignition system that consists of a pulse generator down at the flywheel, an ignition control module, the coil and associated wiring. Also in the mix are safety switches for the clutch and sometimes for the side stand. CDI ignitions are self-powered and the only way to turn them off is to ground the circuits, when they are operating. Try disconnecting the ignition switch and the KILL switch wire connections and check for spark again. Those two switches apply grounding of the CDI circuits to shut the engine off. If you get it back, one of the switches is shorting out internally. If not, then you need to check the pulse generator for output/resistance readings (AC volts cranking or ohms values statically).

You will need a Volt-Ohm meter to test circuits and a simple Suzuki repair manual which gives the correct resistance values and wiring schematics so you know what wires are going where. It usually comes down to eliminating the known good components to determine the actual defective one. Even though it has low miles, the bike is 17 years old and corrosion can build up inside of wiring connectors and vibration can cause wiring fractures or loosen connections throughout the bike. Strip off the bodywork and start from one end of the harness and go through all connections, including grounds.

Bill Silver