fuel cap YAMAHA YZ450F 2012 User Guide

6-2
FUEL TANK
REMOVING THE FUEL TANK
1. Extract the fuel in the fuel tank through the fuel tank cap with a
pump.
Be careful not to damage the fuel
pump.
2. Remove: • Fuel pump coupler
Although the fuel has been re-
moved from the fuel tank be care-
ful when removing the fuel hoses,
since there may be fuel remaining
in it.
• Before disconnecting the fuel hose, clean the area around the fuel hose
connector.
• Before removing the fuel hose, place a few rags in the area under
where it will be removed.
• To disconnect the fuel hose from the fuel tank, remove the fuel hose
connector holder "a", and then slide
the fuel hose connector cover.
• Slide the fuel hose connector cover "1" in the direction of the arrow
mark, and press the buttons "2" on
both sides of the connector to re-
move the fuel hose.
• Disconnecting the hose is done by hand. There is no need to use tools.
• To prevent sand, dust, and other
foreign material from entering the
fuel pump, install the included fuel
hose joint cover 1 "3" and fuel hose
joint cover 2 "4" onto the fuel pump
and disconnected fuel hose.
3. Remove:•Fuel tank
Do not set the fuel tank down so that
the installation surface of the fuel
pump is directly under the tank.
REMOVING THE FUEL PUMP
1. Remove:•Fuel pump
Do not drop the fuel pump or give
it a strong shock.
CHECKING THE FUEL PUMP
BODY
1. Check:
• Fuel pump bodyCracks/damage → Replace fuel
pump assembly.
CHECKING THE FUEL PUMP
OPERATION
1. Check: • Fuel pump operationRefer to "CHECKING THE FUEL
PRESSURE" section.
INSTALLING THE FUEL PUMP
1. Install: •Fuel pump
• Fuel pump bracket
•Do not damage th e installation
surfaces of the fuel tank when in-
stalling the fuel pump.
• Before installing the fuel pump,
remove any dirt and other foreign
material from the installation sur-
face on the fuel tank.
• Always use a new fuel pump gas- ket.
• Install the lip on the fuel pump gas- ket upward.
• Install the fuel pump as shown in
the illustration.
• Align the projection "a" on the fuel pump with the slot in the fuel pump
bracket. Align the slot "b" on the fuel
tank damper with the projection "a"
on the fuel pump.
• Tighten the fuel pump bolts in stag- es in a crisscross pattern.
INSTALLING THE FUEL TANK
1. Install:•Fuel hose
•When installing the fuel hose,
make sure that it is securely con-
nected, and that the fuel hose
holders are in the correct posi-
tion, otherwise the fuel hose will
not be properly installed.
• Be sure not to kink or pinch the
fuel hose.
• Insert the fuel hose on the fuel pipe
until you hear a definite "click".
• Slide the fuel hose connector cover
"1" at the fuel hose end in the direc-
tion of the arrow.
• Install the fuel hose connector hold-
er "a".
• Make sure that the fuel hose and fuel pump lead are routed through
the guide on the cover.
Fuel pump bracket bolt
4 Nm (0.4 m•kg, 2.9
ft•lb)

7-3
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap testSpark→• *Clean or replace spark plug.
• Check the connection of the spark plug cap to the
spark plug.
No spark↓
Check entire ignition system for connection.
(couplers, leads and ignition coil)No good→
Repair or replace.
OK↓
Check engine stop switch. No good→Replace.
OK↓
Check ignition coil. (primary coil and secondary
coil)No good→
Replace.
OK↓
Check AC magneto. (crankshaft position sensor
and stator coil)No good→
Replace.
OK↓
Replace ECU.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-03112-C/90890-03112