Honda VTX 1800 No-Start Troubleshooting
Troubleshooting a Honda motorcycle that won’t start is a relatively straightforward process, and it starts with accessing the electrical system.
To get to the electrical system on a Honda VTX 1800, remove the seat and the two engine side covers. The seat is secured by one bolt on either side just above the point the rear shocks meet the frame. The side covers clip off by pulling outward.
Move the ECU (which sits above the battery) out of the way. Avoid disconnecting the ECU’s wiring, as repeated disconnection and reconnection wears out the electrical connecting pins. Finally, remove the three screws that hold the top battery cover, followed by the cover itself.
Test the Battery
Use a multimeter to test the battery’s condition. A healthy battery should register about 12.5 volts when resting. If the battery is below 12 volts, charge it or replace it and then start the engine.
If the battery is properly charged but the engine still won’t run, it’s time to check the main fuses.
Check the Main Fuses
There’s a cluster of 30 amp fuses on the left side of the battery. The first fuse (L to R) governs the starter circuit; the second fuse governs the ECU and control circuits; and the third fuse is a spare.
Check both active fuses with a test light to determine whether both sides of each fuse has power. Replace any blown fuses and then start the motor. If this doesn’t fix the problem, it’s time to test the solenoid.
Test the Starter Solenoid
The starter solenoid is found just below the 30 amp fuses on the left side of the battery. To check that the solenoid is receiving power, connect a test light to the solenoid terminal that houses the yellow wire with the red stripe that runs from the starter button. Press the starter button and the test light should come on.
To check the solenoid is sending power to the starter motor, connect a test light to the heavy duty solenoid terminal with the thick cable running to the starter motor. Press the starter button and the test light should come on.
NOTE: You should hear the solenoid making a clicking sound as its internal switch activates when the starter button is pressed.
If the solenoid is working but the VTX 1800 still refuses to run, the starter motor is probably faulty and needs to be replaced. When the solenoid isn’t registering power at the terminal that houses the yellow wire with the red stripe, jump a wire from that terminal to the heavy duty terminal that runs to the starter motor.
If the starter engages and the engine starts running when the ignition is on, the problem could be with the connector that governs the starter button and the engine run/kill switch.
Test the Starter & Run/Kill Switch Connector
Remove the headlight unit and pull it out of the way. Find the nine-pin connector that leads to and from the starter button and run/kill switch assembly.
Connect the test light on the battery’s negative terminal and test the terminal in the nine-pin connector that houses the white wire with a black stripe. If the test light comes on with the ignition on, the connector is receiving power from the battery.
Next, test the terminal housing the yellow wire with a red stripe that runs to the solenoid. If the light fails to come on with the ignition on, the problem is the start button or the run/kill switch on the handlebars and the switch assembly needs to be replaced.
Test the Failsafe Circuit
The Honda VTX 1800 has a failsafe mechanism built in that prevents the engine from running if the side stand is extended. If this circuit fails, it can cut the engine when the bike is put in gear even after the side stand is raised.
If your bike fires up but then stops the moment you put it into gear, check the failsafe circuit. Connect a test light to the positive terminal of the battery, then with the ignition on, test the two connectors at the base of the clutch lever. The test light should illuminate when connected to each of the connectors. If neither connector activates the test light, the problem is somewhere in the side stand circuit.
Our first Honda motorcycle no-start troubleshooting tip was to check the battery. Watch the video above for a more in-depth look at diagnosing a bad Honda VTX 1800 battery.