Honda CRF50F 2007 Owner's Manual page 150

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
Federal regulations prohibit removing or
disabling a device or element of design that
may affect your engine's emission
performance unless your motorcycle will be
used exclusively in competition. If you modify
your engine for use in sanctioned competition
events, you must deface or destroy the
emission control information label.
Emission Control Systems
Technical Information
141