Q&A for How to Clean Spark Plugs

There's a special tool you can use that's similar to sandblasting—the tool has an air compressor that's attached to a pouch with sand in it, and you attach the spark plug to that, and it cleans the electrode of the spark plugs with the sand.

Yes, you can use WD-40 to clean spark plugs and also make them easier to remove. Additionally, a coating of WD-40 can help repel water from your spark plugs and prevent corrosion.

You can clean a fouled spark plug and reuse it, but it might not function as well after that. If your spark plug is too worn or dirty to clean easily, you’ll need to replace it.

There may be a problem with your spark plugs if your check engine light is on, your engine runs rough, or your car takes too long to start or accelerate. You might also hear a ticking noise under your hood or notice a bad smell (like rotten eggs) in your exhaust. If you notice any of these problems, check your spark plugs to see if they appear dirty, greasy, charred, worn, or damaged.

The wire brush and cleaning fluid approach above is usually the best method. Other ways are sandblasting with small kits for that purpose, but while that will work, it often leaves abrasive grit in the plug that will eventually come out and damage your cylinder. Some people use a torch to burn off the carbon, but that runs the risk of damaging your plug if you exceed the heat range of the plug. The acid approach works well, but is a little risky for the user.

Always use wire gauge-type gap gauges as coin-type gap gauges can damage the electrode and cause misfiring of the plug.

Press the clutch down, switch to second gear, and start pushing your motorcycle (by yourself or with some help from a friend). Then release the clutch and give it some gas and it should start. However, it might be hard to push it, so consider trying this on a downhill slope.

The gap should be 0.54.

Be careful. Directly below is your piston. Use compressed air to blow any debris out before reinstalling your plug.

You could try aluminum foil on the spark plug, on the part that screws in. This will mend to the port when you put it in.

Check to ensure your air intake/filter/ducts are all clear. Other possibilities are the mass airflow sensor and the throttle body. The engine is supposed to start very rich (automatic choke), but then the airflow should increase quickly once it's started. A badly-plugged air filter will prevent proper airflow, something plugging the intake or duct will do the same thing. The mass airflow sensor usually wouldn't cause this problem, but it might. A stuck or very gummed-up throttle plate might get stuck in the choke position.

Most modern spark plugs do not have an adjustable gap. To "Gap Test" a spark plug, you need a set of feeler gauges which you insert into the end of the spark plug, between the electrode and the tip. If you can slide the correct gauge in without any gap between the electrode and the tip, then the gap is correct. If the plug is heavily corroded or the wrong plug size, you will likely need to replace them with the correct ones.