Fuel Cock - Yamaha XTZ 125K Owner's Manual

Fuel cock

The fuel cock supplies fuel from the tank to the carburetor
while filtering it also.
The fuel cock has three positions:
OFF:
With the fuel cock in this position, fuel will not flow. Always
set the fuel cock to this position when the engine is not
running.
ON:
With the fuel cock in this position, fuel flows to the
carburetor. Set the fuel cock to this position when starting
the engine and while riding.
RES:
This indicates reserve. If you run out of fuel while riding,
set the fuel cock to this position.
Fill the tank at the first opportunity. Be sure to set fuel cock
back to "ON" after refueling!
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