market dynamics
Motorcycle basic circuit fault detection methods and tips.
Release date:2020.06.23

1. It's an observation test

Observe and check whether the circuit lead, the CPU plug, the socket is deformed or damaged, the contact between the plug and the socket is not good, the wire head welding falls off, the contact is defective, the wire is broken, etc. Observe whether the surface color of electrical components changes. For example, CDI igniter, rectifying regulator housing seal resin is scorched or damaged (see figure below), coil enamelled wire insulation deterioration produces odor, etc.

Check the detection lamp: the green grounding wire and the red wire are connected with the positive and negative terminals of the battery in parallel. Start the engine. When the engine speed reaches 5000r/min, observe the light intensity of the test lamp and the reading of charging voltage of the multimeter, and judge whether the battery charging is normal (see the figure below).


Check the lighting circuit fault. The test lamp is earthed at one end and connected with the suspected faulty wire at the other end. Observe whether the bulb shines or not.

2. It is easy before difficult inspection

That is, do not disassemble when repairing circuit fault. Remove engine parts that can be easily removed first or remove and repair immediately without damaging the plastic housing. When the fault cannot be removed, then remove the necessary complex components for maintenance.

Example: Signal circuit failure (turn signal does not flash) : do not remove any components, unplug the turn signal and power plug. The multimeter is set in DC25V, the black marker is grounded, and the red marker is connected with the steering signal line respectively. Toggle the steering switch to determine the fault point: the multimeter has no voltage indication, indicating that the flash relay, turn signal and steering switch have faults. When there is voltage indication: flash relay, steering switch normal, turn lamp filament broken, bulb and lamp holder contact is bad.

3.. Multimeter and detector test

The multimeter is installed with ac voltage shield (AC10~200V) to check whether the output AC voltage of the magneto is normal.

The multimeter sets DC25V block to detect the dc output voltage of the power supply device, namely the rectifier regulator, and the DC power supply voltage of the battery. Check dc voltage of dc power cord to ground.

Specific detection methods:

The multimeter is equipped with AC10~ 200V gear to detect the CDI charging ignition coil and trigger coil of the magneto and output ac voltage (30-100V). Ac voltage output by magneto lighting coil (30-70V); Three-phase magneto output ac voltage (30-150V). When the AC current is low or no AC voltage, it indicates that the trigger coil magneto stator coil and magneto rotor have hard faults.

The multimeter is equipped with DC voltage DC25V to test the charging DC voltage of the battery (12-16V). For all DC powered vehicles, test the charging voltage of battery (12-14.5V/5000r/min) and dc voltage of power supply of headlight (12-16V).

The fault of electric jet motorcycle (circuit, oil circuit) is more time-consuming to detect. It is difficult to detect and troubleshoot a single digital multimeter. The fault detector and multimeter should be used for inspection respectively.