Honda CB1000RA 2021 Owner's Manual page 170

Emission Control Systems
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Catalytic Converters
The exhaust system contains one or more
catalytic converters. Catalytic converters use a
catalyst to convert most of the harmful exhaust
gas compounds into harmless compounds.
Evaporative Emission Control System
50 STATE (meets California)
An evaporative emissions control system uses a
canister filled with charcoal to adsorb fuel vapor
from the fuel tank while the engine is off. The
vapor is drawn into the engine and burned
while riding.
Crankcase Emissions Control System
The engine is equipped with a closed crankcase
system to prevent discharging crankcase
emissions into the atmosphere.
Blow-by gas is returned to the combustion
chamber through the air cleaner housing and
throttle body.
166
Fuel Permeation Emission Control
The fuel tank, fuel hoses, and fuel vapor charge
hoses use fuel permeation control technologies
to prevent fuel vapor emissions. Tampering with
these components to reduce or defeat the
effectiveness of the fuel permeation
technologies is prohibited.