Honda Rebel 250 2016 Owner's Manual page 8

Safety Guidelines
Carbon Monoxide Hazard
Exhaust contains poisonous carbon monoxide,
a colorless, odorless gas. Breathing carbon
monoxide can cause loss of consciousness and
may lead to death.
If you run the engine in confined or even partly
enclosed area, the air you breathe could contain
a dangerous amount of carbon monoxide.
Never run your motorcycle inside a garage or
other enclosure.
6
WARNING
3
Carbon monoxide gas is toxic.
Breathing it can cause
unconsciousness and even kill you.
Avoid any areas or activities that
expose you to carbon monoxide.