Motorcycle Ignition Problems
Motorcycle ignition systems are exposed to very harsh operating conditions. Many components are exposed to the elements. High engine temperatures effect the components and cause insulation breakdown (IB), especially on air-cooled models. Vibration is more pronounced on motorcycles, which can lead to early component failure. While the components are built with these considerations in mind, the components still fail occasionally and either disrupt or disable the ignition system.
Troubleshooting the Components
Each component of the ignition system may be individually tested, starting at the end of the system and working to the other end. Isolate and de-energize each component, starting with the spark plugs. Pull the plugs and check for fouling and poor spark plug gapping. Pull the spark plug wires off of the coil and perform a resistance check through each wire. Check for resistance and IB through both the primary and secondary side of the ignition coil. Check the crankshaft position sensor for resistance and damage and insure that it is properly positioned. Replace any damaged or out-of-specification parts.
The ignition module controls the timing of the ignition based on engine RPMs and information from the crankshaft position sensor. Built with solid-state construction and aided by a programmed-in power curve, the ignition module delivers electricity to the primary side of the ignition coil, causing the plugs to fire at the optimal time. Ignition modules cannot be tested, but must instead be identified as bad through a process of elimination. Test all other components and associated wiring first and if they all test as good, then the ignition module must be bad.
Things You Will Need
A complete set of mechanic’s tools is a must, in both standard and metric. A good, click type (not swing-bar type) 3/8 inch torque wrench is another must-have so the proper torque can be applied during reassembly. Buy an electrical testing tool (multi-meter) to make your continuity, resistance and IB tests. Meters with digital displays instead of analog are easier to use, more accurate and usually can perform a wider variety of tasks than analog meters.