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Yamaha yz450f 2012 Service Manual

Yamaha yz450f 2012
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3-11
ENGINE
ADJUSTING THE VALVE
CLEARANCE
This section is intended for those
who have basic knowledge and skill
concerning the servicing of Yama-
ha motorcycles (e.g., Yamaha deal-
ers, service engineers, etc.) Those
who have little knowledge and skill
concerning servicing are requested
not to undertake inspection, adjust-
ment, disassembly, or reassembly
only by reference to this manual. It
may lead to servicing trouble and
mechanical damage.
The valve clearance should be ad-
justed when the engine is cool to
the touch.
1. Remove:
Seat
Refer to "SEAT AND SIDE COV-
ERS" section in the CHAPTER 4.
Fuel tank
Refer to "FUEL TANK" section in
the CHAPTER 6.
2. Remove:
Spark plug
Cylinder head cover
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
3. Remove:
Timing mark accessing screw "1"
Crankshaft end accessing screw
"2"
O-ring
4. Check:
Valve clearance
Out of specification Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the alignment mark "a" on
the rotor with the alignment mark
"b" on the crankcase cover.
Make sure that the alignment mark
"c" on the exhaust camshaft sprocket
and the alignment mark "d" on the in-
take camshaft sprocket are aligned
with the edge of the cylinder head.
c. Measure the valve clearance "e"
using a feeler gauge "1".
Record the measured reading if the
clearance is incorrect.
5. Adjust:
Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and
exhaust).
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
b. Remove the valve lifter "1" and
the valve pad "2" with a valve lap-
per "3".
Place a rag in the timing chain
space to prevent pads from falling
into the crankcase.
Identity each valve lifter and pad
position very carefully so that they
can be reinstalled in their original
place.
c. Select the proper pad using the
pad selecting table.
The thickness "a" of each pad is indi-
cated in hundredths of millimeters on
the pad upper surface.
Engine idling speed:
1,900–2,100 r/min
Valve clearance (cold):
Intake valve:
0.10–0.15 mm
(0.0039–0.0059 in)
Exhaust valve:
0.20–0.25 mm
(0.0079–0.0098 in)
Pad range
Pad Availabili-
ty: 25 incre-
ments
No.
120–N
o. 240
1.20
mm–2.
40 mm
Pads are avail-
able in 0.05 mm
increments

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Yamaha yz450f 2012 Specifications

General IconGeneral
Bore x Stroke97.0mm x 60.8mm
Compression Ratio12.5:1
Fuel DeliveryFuel Injection
Transmission5-speed
Final DriveChain
Tires Front80/100-21
Tires Rear120/80-19
Wheelbase58.7 in
Trail4.6 in
Fuel Capacity1.6 gal
Wet Weight245 lb
Engine TypeLiquid-cooled, 4-stroke, DOHC, 4-valve
IgnitionTCI
Suspension FrontTelescopic fork, 12.2 in travel
Suspension RearSwingarm, 12.4 in travel
Brakes FrontHydraulic single disc brake, 250mm
Brakes RearSingle disc, 245 mm

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