Honda CRF70F 2009 Owner's Manual page 87

3. Use a brush to remove carbon deposits from
the spark arrester screen. Be careful to avoid
damaging the spark arrester screen. The
spark arrester must be free of breaks and
holes. Replace, if necessary. Check the
gasket. Replace, if necessary.
4. Install the spark arrester and the gasket in the
muffler and tighten the bolts securely.
Spark Arrester
Servicing Your Honda
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