Overhauling your motorcycle: checking and changing spark plugs

We're not professional mechanics, just motorcycle enthusiasts who want to share our knowledge. So if you end up in hospital after accidentally ingesting spark plugs, Ixtem Moto cannot be held responsible. In any case, we advise you to change your spark plugs according to the frequency indicated by the manufacturer.

To change your spark plugs, you need

• A motorcycle, in our case our friend's Kawette ER6 2006.
• A toolbox with standard equipment (flat keys, Allen keys, etc.). Often, you'll only need the tools in your motorcycle's tool kit .
• Specific tools and products: a spark plug wrench (from the tool kit?). Degreaser (if necessary), motor oil or special high-temperature grease and an air compressor (not compulsory).
• Consumables: spark plugs adapted to your motorcycle. Find out how many spark plugs you need. Trap: some bikes have 2 spark plugs per cylinder!)
• The owner's manual or a technical magazine to find out where the spark plugs are located.

1. Disassembly

Like any self-respecting weekend do-it-yourselfer, think "organization". You're going to unscrew a number of different screws, and you don't want to mix them up... or risk spending several days reassembling your bike! To do this, try to sort your screws using old jars or small labels (something I rarely do, but it saves time!).

Once you know where your spark plugs are, carefully unscrew the necessary parts. Try to have your fuel tank almost empty before you start, as in many cases handling it will be necessary. In our case, we had to remove the fuel tank and airbox.

Under the airbox are the "big holes" for the air intake, with the "butterflies" ajar (it rhymes!). As a precaution, we plugged them with small rags... it would be a shame to drop a screw into the engine!

2. Accessing the spark plugs

They're underneath the suppressors. These supply the spark plugs with electricity and protect them from the outside environment. To remove them, simply unplug them (not systematically), then pull on them.

They need to be replaced in their original cylinders. So if you're afraid of getting your fingers tangled when reassembling a motorcycle with 6 or more cylinders, proceed one after the other, or mark them with labels. At the bottom of the hole(s) are the spark plugs. If you have a compressor, you can use a blowgun to clean out the "wells" before removing the spark plugs. As always, try to clean everything in front of you or in your hands!

3. Removing spark plugs

Insert your spark plug wrench into the well and turn it gently so that it "clips" into the plug. Then loosen it completely.

If it's seized up, warm up your engine. Once expanded, your spark plug will unscrew more easily (watch out for burns! ask someone else to do it for you while you go to the toilet).

4.check the condition of your candle

Check the condition of the electrodes.

• If they are light brown or light grey in color, your candle is in good condition and your combustion is good. It is not essential to change your candle.
• If the electrodes are white or shiny: your carburetion is too lean, and there's a risk of overheating and, in the worst case, engine failure! Ask for a carburetion/mapping check.
• If they are black and dry. Carburation is too rich or incomplete. It's best to change your spark plugs and ask for a carburetion/mapping test.
• If they are black and greasy. The carburetor is too rich or incomplete... and your brelon is "eating" oil. You'll need to change your spark plugs and take your bike to the dealer for a check-up.

If you want to reuse your spark plug: before reassembling it, check that the gap between the two electrodes is not too wide (generally 1mm is OK, more is not so good). If the rest of the spark plug is rusted or damaged, you'll also need to replace it (in our case), as it may not work properly.

5. Reassembly

Take a new spark plug, then lightly lubricate the thread with your finger ("put your Vaseline away... you need motor oil or high-temperature grease!").

"Clip the new spark plug onto the wrench... then push it into the hole. Start screwing by hand, but don't force it, as your spark plug needs to settle on the thread. When you feel it has "settled", screw on! Once you've reached the stop, you can use an open-end wrench to lever the screw in, tightening it no more than ¼ turn.

Now you've changed your spark plug! You can do the same for the others. Next, don't forget to put your fuel tank back in place! If you don't, your machine may have trouble starting ;-).

Last but not least: recycle your waste (an old candle on a birthday cake will go unnoticed)!

Next step: cleaning or changing your air filter!