All-OffRoad - Tech-Tips
Dealing with a Fouled Spark Plug
Over the years Ive heard of several ways to deal with
fouled spark plugs. The most sure-fire way to eliminate the problem is to buy a
four-stroke. However, for many thats not an option. So with that in mind heres
a couple of other tips:
- The most important thing is to ensure the jetting is correct. With
the correct jetting there is less chance of fouling the plug.
- Almost as important is to carry at least one extra spark plug. No
matter how spot-on the jetting is, theres still a chance of fouling, especially when
riding in areas with extremely varied elevations. I usually end up carrying four. One for
me and one (or three) for anyone else in the group.
- So what do you do if youve if youve fouled all of your
plugs? Carry a small piece of emery cloth or fine-grit sandpaper. Use this to clean up the
plug, blowing the plug clean occasionally. A little bit of gas can be used to rinse some
of the nastier goop away. On occasion Ive actually used a small nail file and on one
occasion I used the little tin inner tube buffer out of a patch kit (this is not
recommended but it did work when used with a little gas).
- If your out in the desert and have forgotten to bring sandpaper, a
nail file, or a patch kit, Ive heard of people using sand. Again, use a little gas
to rinse the plug clean.
- Ive also heard of this little trick (though I don't
- Pull the spark plug cap away from the plug until there is ¼ inch
between the plug and the metal clamp in the plug boot.
- The rubber boot should still fit tightly on the plug, if not try
using a zip-tie to tighten it in place.
- Start the bike and let it run for about a minute. This should
clean the plug.
- Press the boot all the way down and you should be "good to
This could potentially damage the ignition on some bikes and
should only be used as a last ditch effort. While I have never had to try this and
cant attest to it actually working, several people have reported to have used it
successfully. In theory, this increases the resistance allowing the coil to increase its
charge. The downside is that it could toast the coil and other sensitive ignition parts.
After cleaning the electrodes, a credit card can be used as an
impromptu gap gage. Everyone rides with credit cards (or at least an insurance card),
All of these tips have allegedly worked for one person or
another. They may or may not work for you, but in a pinch they are something to try. As
with anything, use common sense, take precautions, and dont try anything you think
is a stupid idea