ENGINE
3-6
EAM20135
ENGINE
EAM30226
ADJUSTING THE VALVE CLEARANCE
TIP
•
This section is intended for those who have ba-
sic knowledge and skill concerning the servic-
ing of Yamaha motorcycles (e.g., Yamaha
dealers, service engineers, etc.). Those who
have little knowledge and skill concerning ser-
vicing are requested not to undertake inspec-
tion, adjustment, disassembly, or reassembly
only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
•
Make sure that the valve clearance is checked
or adjusted while the engine is cold (at room
temperature).
•
While the valve clearance is checked or adjust-
ed, make sure that the piston is positioned in
the top dead center (TDC).
1. Remove:
•
Seat
•
Side cover (left/right)
•
Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-1.
•
Fuel tank
Refer to “FUEL TANK” on page 7-1.
•
ECU
2. Remove:
•
Spark plug
•
Cylinder head cover
Refer to “CAMSHAFT” on page 5-13.
3. Remove:
•
Timing mark accessing screw “1”
•
Crankshaft end accessing screw “2”
•
O-ring
4. Check:
•
Valve clearance
Out of specification
Regulate.
a. Turn the crankshaft counterclockwise with
a wrench.
b. Align the top dead center (TDC) mark “a”
on the generator rotor with the alignment
mark “b” on the crankcase cover.
TIP
Check that the alignment marks “c” on the cam-
shaft sprockets are aligned with the edge of the
camshaft cap surfaces “d”.
c. Measure the valve clearance using a
thickness gauge “1”.
TIP
Record the measured reading if the clearance is
incorrect.
1
2
Valve clearance (cold)
Intake
0.10–0.17 mm (0.0039–0.0067 in)
Exhaust
0.15–0.22 mm (0.0059–0.0087 in)
Thickness gauge
90890-03268
Feeler gauge set
YU-26900-9
b
a
d
d
d
c
d
d
c
Summary of Contents for YZ450F 2021
Page 6: ...EAM20162 YAMAHA MOTOR CORPORATION U S A YZ MOTORCYCLE LIMITED WARRANTY ...
Page 10: ......
Page 44: ...MOTORCYCLE CARE AND STORAGE 1 32 ...
Page 61: ...TIGHTENING TORQUES 2 16 ...
Page 62: ...CABLE ROUTING DIAGRAM 2 17 EAM20152 CABLE ROUTING DIAGRAM Frame and engine left side view ...
Page 64: ...CABLE ROUTING DIAGRAM 2 19 Frame and engine right side view ...
Page 66: ...CABLE ROUTING DIAGRAM 2 21 Handlebar front view ...
Page 68: ...CABLE ROUTING DIAGRAM 2 23 Frame and engine top view ...
Page 70: ...CABLE ROUTING DIAGRAM 2 25 Frame and battery top view ...
Page 72: ...CABLE ROUTING DIAGRAM 2 27 Rear brake right side view ...
Page 74: ...CABLE ROUTING DIAGRAM 2 29 ...
Page 112: ...ELECTRICAL SYSTEM 3 36 ...
Page 148: ...REAR BRAKE 4 34 system Refer to BLEEDING THE HYDRAULIC BRAKE SYSTEM on page 3 25 ...
Page 189: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 5 3 1 Connecting rod 2 Oil nozzle 3 Crankshaft ...
Page 191: ...LUBRICATION SYSTEM CHART AND DIAGRAMS 5 5 1 Oil filter element 2 Oil pump 3 Oil strainer ...
Page 262: ...TRANSMISSION 5 76 ...
Page 272: ...WATER PUMP 6 9 ...
Page 282: ...THROTTLE BODY 7 9 ...
Page 289: ...IGNITION SYSTEM 8 6 ...
Page 290: ...ELECTRIC STARTING SYSTEM 8 7 EAM20143 ELECTRIC STARTING SYSTEM EAM30279 CIRCUIT DIAGRAM ...
Page 294: ...CHARGING SYSTEM 8 11 EAM20144 CHARGING SYSTEM EAM30282 CIRCUIT DIAGRAM ...
Page 297: ...CHARGING SYSTEM 8 14 ...
Page 298: ...FUEL INJECTION SYSTEM 8 15 EAM20145 FUEL INJECTION SYSTEM EAM30284 CIRCUIT DIAGRAM ...
Page 321: ...FUEL INJECTION SYSTEM 8 38 ...
Page 322: ...FUEL PUMP SYSTEM 8 39 EAM20146 FUEL PUMP SYSTEM EAM30287 CIRCUIT DIAGRAM ...
Page 352: ...SELF DIAGNOSTIC FUNCTION AND DIAGNOSTIC CODE TABLE 9 15 ...
Page 362: ...CHASSIS 10 9 ...
Page 364: ......
Page 366: ......
Page 368: ...YZ450FM 2021 WIRING DIAGRAM B2W 2819U 11_W D indd 2 2020 02 05 10 21 39 ...