Honda PIONEER SXS500M 2020 Owner's Manual page 233

Emission Control Systems
Problems That May Affect Exhaust Emissions
If you are aware of any of the following symptoms, have the vehicle
inspected and repaired by your dealer.
Symptoms:
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 Honda 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.
If you loan, sell, or give your competition modified Honda to
someone else, according to applicable law, you must inform the new
owner/operator in writing that the vehicle is to be used for
competition only.
226 Technical Information