Honda 2004 XR400R Owner's Manual page 177

Emission Control Systems
Problems that May Affect Motorcycle
Emissions
If you are aware of any of the following
symptoms, have the vehicle inspected and
repaired by your Honda Motorcycle Dealer:
1. Hard starting or stalling after starting
2. Rough idle
3. Misfiring or backfiring during acceleration
4. After-burning (backfiring)
5. Poor performance (driveability) and poor
fuel economy
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Technical Information