Yamaha DT501988 Owner's Manual page 13

GASOLINE AND EXHAUST GAS
1. GASOLINE IS HIGHLY FLAMMABLE:
a. Always turn off the engine when refueling.
b. Take care not to spill any gasoline on the engine or exhaust
pipe(s)/muffler(s) when refueling.
c. Never refuel while smoking or in the vicinity of an open flame.
2. Never start the engine or let it run for any length of time in a closed area.
The exhaust fumes are poisonous and may cause loss of consciousness and
death within a short time. Always operate your motorycle in an area that
has adequate ventilation.
3. Always turn off the engine before leaving the motorcycle unattended and
remove the ignition key. When parking the motorcycle, note the following:
a. The engine and exhaust pipe(s)/muffler(s) may be hot. Park the motorcycle
in a place where pedestrians or children are not likely to touch these hot
areas.
b. Do not park the motorcycle on a slope or soft ground: the motorcycle
may fall over.
c. Do not park the motorcycle near an flammable source, e.g. a kerosene
heater, or near an open flame. The motorcycle could catch fire.