Check Spark Plugs In A Harley Nightster

Spark plugs make your Harley Nightster‘s engine function.

Spark plugs ignite the fuel that runs all internal combustion engines, including the one on your Harley Nightster. When your spark plugs or spark plug wires are not functioning properly, your engine’s performance will be altered. If all of your spark plugs are not functioning properly, your engine won’t function at all. It is important to check your spark plugs if you notice any change in your engine’s performance. Checking the spark plugs of your Harley Nightster involves a series of simple functionality tests.


Check the Functionality of Spark Plugs and Wiring

1. Start the engine on your Nightster.

2. Remove one of spark plug wires connected to one of the spark plugs on the left side of your Nightster’s engine block while the engine is running. The wires can easily be pulled off the top of the spark plugs by hand. If the engine starts to cough and sputter, the plug is fine. If the engine continues to idle as normal, the plug may be bad or dirty and need to be replaced. Repeat the process with the other plug.

3. Hold the end of the spark plug wire against a metal surface. If a spark arcs from the end of the wire to the piece of metal, the wiring is fine. If there is no sparking or snapping, the wiring for that particular plug is faulty and needs to be replaced.

Check the Attachment of the Spark Plugs

4. Remove the spark plug wires while the engine is off.

5. Clean the area around the spark plug with compressed air. If you have a compressed air gun, you can use that. If you don’t, you can use a can of compressed air that you would use for cleaning a computer keyboard.

6. Crack each spark plug with a ratchet wrench that has a spark plug socket attached to the end of a socket extender. A socket extender is a long piece of metal tubing that allows you to extend the socket connection point. A spark plug socket can be purchased at any auto parts or hardware store. It has a piece of protective padding on the inside of the socket that protects the spark plug when it is removed from the engine.

7. Unscrew and remove the spark plugs by hand after you have sufficiently cracked them.

8. Clean the connection points of the spark plugs with compressed air and a clean cloth.

9. Lubricate the connection point of the spark plugs with dielectric grease. You can purchase dielectric grease from any auto parts store.

10. Reinstall the spark plugs and repeat the functionality test.