Troubleshooting Motorcycle Starter Solenoid Relay Problems: Causes and Solutions
Part 1 :Faulty starter solenoid Clicking but not turning
It is a very common sign that the engine will not start if you hear a single or rapid clicking noise coming from the solenoid relay area when you turn the ignition key or press the starter button. The clicking noise means that the solenoid is being energized and trying to engage, but is unable to complete the circuit to the starter motor. This could be caused by a low battery voltage that provides just enough power to make the solenoid click, but not enough to engage the starter, or it could be caused by a faulty contact inside the solenoid that prevents the current from being fully transmitted to the starter.
For example, if the battery is old and low, or if corrosion on the battery terminals causes a drop in voltage, the solenoid may make a clicking sound and fail to start the engine.
1.2 The engine won't start at all
When you try to start your motorcycle, nothing happens at all. The solenoid may not be receiving power due to a blown fuse in the starting circuit, a faulty ignition switch, or a broken wire between the battery and the solenoid. In this case, it's not just the solenoid itself that's at fault, but the solenoid may be part of an overall electrical problem. For example, if the wires connected to the solenoid are damaged by rubbing against the frame during vibration, the solenoid will not get a signal to engage and the engine will not start.
Intermittent startup problems
Sometimes your motorcycle starts fine and sometimes it doesn’t. This could be a sign of a faulty solenoid relay. Intermittent behavior can be caused by loose or corroded electrical connections at the solenoid terminals. Vibrations from riding can cause these connections to sometimes work and sometimes not. Also, internal components of the solenoid, such as worn springs or loose contacts, can cause intermittent engagement.
1.3 Electromagnetic relay overheating
If the solenoid relay becomes too hot to touch after trying to start the engine a few times, this indicates a problem. Excessive current draw, usually caused by a short in the starter motor or wiring, can cause the solenoid to overheat. For example, if the insulation on the starter motor windings is damaged and creates a short circuit, more current than normal will flow through the solenoid, causing it to heat up. Another cause could be a solenoid that is stuck in the engaged position, constantly passing current and overheating.
1.4 Slow start before failure
Before the solenoid fails completely, the engine starts slower than usual. This may indicate that the solenoid contacts are worn or have poor conductivity. As the contacts degrade, they are unable to effectively transfer full current to the starter motor, resulting in slower starts. Over time, this problem worsens until the starter motor fails to start at all.
PART 2 : Fault Analysis and Solutions of Motorcycle Starting Solenoid Relay
Solution
- Problem: The electromagnetic relay makes a clicking sound, but the motorcycle starter does not turn
Possible causes:
Low battery voltage: If the battery is low or discharged, it may not provide enough power to the solenoid relay to fully engage the starter. The clicking sound is the solenoid trying to engage, but it cannot complete the circuit with the starter motor due to insufficient power. This problem may occur, for example, if the motorcycle has been parked for a long time without charging the battery, or if there is a parasitic drain on the battery.
Loose or corroded battery terminals: A poor electrical connection at the battery terminals can cause voltage to drop. Corrosion at the terminals acts as an insulator, preventing electrical current from flowing properly. Even if the battery is fully charged, the solenoid may not receive the full voltage it needs for the starter.
Faulty solenoid relay contacts: Over time, the contacts within the solenoid relay can become worn or pitted. This can prevent current from properly transferring from the battery to the starter motor, even when the solenoid is trying to engage.
Solution:
Check the battery voltage: Use a multimeter to measure the battery voltage. A fully charged 12 volt motorcycle battery should read around 12.6 - 12.8 volts at rest. If the voltage is lower (less than 12 volts), charge the battery using a suitable battery charger. Always follow the charger's instructions to avoid overcharging.
Inspect and clean the battery terminals: Disconnect the battery cables and inspect the terminals for corrosion. If corrosion is present, clean the terminals using a wire brush and a mixture of baking soda and water. Rinse with clean water and dry thoroughly before reconnecting the cables. Tighten the cable connections to ensure good electrical contact.
Replace the electromagnetic relay: If the battery and connections are in good condition but the problem persists, the electromagnetic relay may be faulty. Replace it with a new one that is compatible with your motorcycle make and model.
- Problem: Starter solenoid valve relay overheats
Possible causes:
Excessive current consumption: This may be caused by a short circuit in the starter motor or in the wiring. When a short circuit occurs, the current flowing through the electromagnetic relay will exceed the normal value, causing the relay to heat up. For example, if the insulation layer of the starter motor winding is damaged, it will cause a short circuit.
Continuous Operation: If the electromagnetic relay becomes stuck in the engaged position, either due to a mechanical problem or a fault in the control circuit, it will continue to pass current through the starting circuit and overheat.
Solution:
Check for shorts: Check the starter motor and its wiring for any signs of damage, such as frayed wires, exposed conductors, or melted insulation. Use an ohmmeter to test the resistance of the starter motor windings. If the resistance is very low or zero, a short circuit has occurred and the starter motor may need to be repaired or replaced.
Check the mechanical and control components of the solenoid relay: Check if the solenoid relay is physically stuck. If so, try to free it or replace it. Also, check the control circuit that activates the solenoid. There may be a problem with the ignition switch, start button, or related relays and wiring that causes the solenoid to remain engaged.
- Problem: Intermittent starting - the starter sometimes works and sometimes doesn't
Possible causes:
Loose or intermittent wiring connections: Vibration during motorcycle driving may cause loose wiring or intermittent connections. This will interfere with the current flow of the electromagnetic relay and starter.
Failure of internal components of the electromagnetic relay: There may be loose or damaged components such as springs or contact arms inside the electromagnetic relay, causing it to work erratically.
Solution:
Check and tighten wiring connections: Check the wiring from the battery to the solenoid relay and from the solenoid relay to the starter motor. Check for any loose connections, damaged wires or connectors. Tighten any loose connections and replace any damaged wires or connectors.
Replace the electromagnetic relay: If the wiring appears to be intact, but the problem persists, the electromagnetic relay itself may be faulty. Replace it with a new high-quality electromagnetic relay to ensure reliable starting.
How to replace a motorcycle starter solenoid relay?
Here are the general steps for replacing a motorcycle starter solenoid relay:
- Preparation
Safety First: Make sure the motorcycle is in a stable position, preferably on a center stand or motorcycle lift. Turn off the ignition and remove the key to prevent accidental starting.
Gather tools: You’ll typically need a set of wrenches (usually metric), a screwdriver (flat or Phillips, depending on the fastener), and possibly some electrician’s pliers.
- Find the electromagnetic relay
The starter solenoid relay is usually located near the battery or starter motor. In some motorcycles, it may be mounted on the frame or bracket. Consult your motorcycle's service manual to find the exact location.
- Disconnect the battery
Always disconnect the negative (-) battery terminal first to prevent electric shock and short circuits. Use a wrench to loosen the nut on the battery terminal, then carefully remove the cable. It is a good idea to wrap the cable end with a plastic bag or electrical tape to prevent it from accidentally contacting the battery terminal during repair.
- Remove the old electromagnetic relay
There will be electrical connections and mounting bolts or screws to hold the electromagnetic relay in place.
Electrical Connections: Use electrical pliers to carefully disconnect the wires connected to the electromagnetic relay. These wires may have push-on connectors or they may have screw terminals. Make a note of which wire goes where, or take a photo for reference if possible. You may need to loosen the locking tabs or unscrew the terminal nuts to disconnect the wires.
Mounting Hardware: After removing the electrical connections, locate the mounting bolts or screws that secure the electromagnetic relay to the frame or bracket. Use an appropriate wrench or screwdriver to remove these fasteners. Then, carefully remove the old electromagnetic relay from its mounting location.
- Install a new electromagnetic relay
Installation: Place the new electromagnetic relay in the same location as the old relay and secure it with the mounting bolts or screws. Tighten them to the recommended torque specifications (usually found in the service manual).
Electrical Connections: Reconnect the wires to the new electromagnetic relay in the correct order. Make sure the connections are secure. If the connector is a push-in type, push firmly until it clicks into place. For screw-type terminals, tighten the nuts to the proper torque to ensure a good electrical connection.
- Reconnect the battery
After installing the new electromagnetic relay and making a secure connection, reconnect the negative (-) battery terminal. Tighten the nut on the terminal to ensure a good connection.
- Test the Launcher
Turn the ignition on and attempt to start the motorcycle. The starter should engage and crank the engine smoothly. If the problem persists, double-check the connections and operation of the solenoid relay. If the problem persists, there may be other issues with the starter motor, battery, or wiring that require further investigation.
Please note that the specific steps may vary depending on the make and model of your motorcycle. It is best to refer to the specific repair manual for your motorcycle for the most accurate and detailed instructions.