Thumpstar ATV 125CC, Owner'S Manual

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ATV 125 - Inspection and Maintenance
SPARK PLUG
Your ATV comes equipped with an AT7C OR A7RTC spark plug. You
can determine if the standard spark plug is suitable for your type of vehicle
usage by observing the color of the plug‘s porcelain center electrode
insulator after vehicle operation. It the plug has the correct heat range, it
should be very light brown in color. If the plug tends to run to cold,
(usually evidenced by blackening or the insulator or a wet electrode)
replace it with an alternate plug according to the following chart.
An improper spark plug may have an incorrect fit or heat range for your
engine, this may cause severe engine damage which may not be covered
under warranty .use one of the spark plugs listed below or equivalents.
Consult your dealer if you are not sure which spark plug is correct for your
type of vehicle usage.
To install a spark plug, turn it in as for as possible with your fingers, and
then tighten it with a wrench. Do not over tighten or cross thread the spark
plug, or the aluminum thread of the cylinder will be damaged. Do not
allow contaminants to enter the engine through the spark plug hole when
the plug is removed.
To maintain a hot, strong spark, keep the plug free of carbon. Remove car-
bon from the plug with a wire or pin, and adjust the gap to 0.6-0.7mm for
good ignition. Use a thickness gauge to check the gap.
Center Electrode
Side Electrode
Insulator