2014 YAMAHA YZ450F width

GENERAL SPECIFICATIONS
2-1
EAS1SL1052
GENERAL SPECIFICATIONS
Model
Model 1SL1 (USA) (CAN)
1SL2 (EUR)
1SL3 (JPN)
1SL4 (AUS) (NZ) (ZAF)
Dimensions
Overall length 2175 mm (85.6 in) (USA) (CAN)
2180 mm (85.8 in) (EUR) (JPN) (AUS) (NZL) 
(ZAF)
Overall width 825 mm (32.5 in)
Overall height 1290 mm (50.8 in) (USA) (CAN)
1280 mm (50.4 in) (EUR) (JPN) (AUS) (NZL) 
(ZAF)
Seat height 975 mm (38.4 in) (USA) (CAN)
965 mm (38.0 in) (EUR) (JPN) (AUS) (NZL) 
(ZAF)
Wheelbase 1480 mm (58.3 in)
Ground clearance 335 mm (13.19 in) (USA) (CAN) (EUR)
330 mm (12.99 in) (JPN) (AUS) (NZL) (ZAF)
Weight
Curb weight 111 kg (246 lb)

ENGINE SPECIFICATIONS
2-2
EAS1SL1053
ENGINE SPECIFICATIONS
Engine
Engine type Liquid cooled 4-stroke, DOHC
Displacement 449 cm3
Cylinder arrangement Single cylinder
Bore  stroke 97.0  60.8 mm (3.82  2.39 in)
Compression ratio 12.50:1
Starting system Kickstarter
Fuel
Recommended fuel Premium unleaded gasoline only
Fuel tank capacity 7.5 L (1.98 US gal, 1.65 Imp.gal)
Engine oil
Lubrication system Wet sump
Recommended brand YAMALUBE
Type SAE 10W-30, SAE 10W-40, SAE 15W-40, 
SAE 20W-40 or SAE 20W-50
Recommended oil grade API service SG type or higher, 
JASO standard MA
Engine oil quantity
Quantity (disassembled) 0.95 L (1.00 US qt, 0.84 Imp.qt)
With oil filter element replacement 0.69 L (0.73 US qt, 0.61 Imp.qt)
Without oil filter element replacement 0.67 L (0.71 US qt, 0.59 Imp.qt)
Oil filter
Oil filter type Paper
Oil pump
Oil pump type Trochoid
Inner-rotor-to-outer-rotor-tip clearance Less than 0.150 mm (0.0059 in)
Limit 0.20 mm (0.0079 in)
Outer-rotor-to-oil-pump-housing clearance 0.13–0.18 mm (0.0051–0.0071 in)
Limit 0.24 mm (0.0094 in)
Oil-pump-housing-to-inner-and-outer-rotor 
clearance 0.06–0.11 mm (0.0024–0.0043 in)
Limit 0.17 mm (0.0067 in)
Cooling system
Radiator capacity (including all routes) 1.04 L (1.10 US qt, 0.92 Imp.qt)
Radiator capacity 0.57 L (0.60 US qt, 0.50 mp.qt)
Radiator cap opening pressure 108–137 kPa (1.08–1.37 kg/cm2 15.7–19.9 psi)
Radiator core
Width 112.6 mm (4.43 in)
Height 235.0 mm (9.25 in)
Depth 28.0 mm (1.10 in)
Water pump
Water pump type Single suction centrifugal pump
Spark plug
Manufacturer/model NGK/CR8E
Spark plug gap 0.7–0.8 mm (0.028–0.031 in)

ENGINE SPECIFICATIONS
2-3
Cylinder head
Volume 25.98–26.78 cm3 (1.59–1.63 cu.in)
Warpage limit 0.05 mm (0.0020 in)
Camshaft
Drive system Chain drive (left)
Camshaft cap inside diameter 22.000–22.021 mm (0.8661–0.8670 in)
Camshaft journal diameter 21.959–21.972 mm (0.8645–0.8650 in)
Camshaft-journal-to-camshaft-cap clearance 0.028–0.062 mm (0.0011–0.0024 in)
Camshaft lobe dimensions
Intake A 37.730–37.830 mm (1.4854–1.4894 in)
Limit 37.630 mm (1.4815 in)
Intake B 27.950–28.050 mm (1.1004–1.1043 in)
Limit 27.850 mm (1.0965 in)
Exhaust A 33.540–33.640 mm (1.3205–1.3244 in)
Limit 33.440 mm (1.3165 in)
Exhaust B 24.769–24.869 mm (0.9752–0.9791 in)
Limit 24.669 mm (0.9712 in)
Camshaft runout limit 0.015 mm (0.0006 in)
Timing chain
Tensioning system Automatic
Valve, valve seat, valve guide
Valve clearance (cold)
Intake 0.13–0.20 mm (0.0051–0.0079 in)
Exhaust 0.20–0.25 mm (0.0079–0.0098 in)
Valve dimensions
Valve head diameter A (intake) 36.90–37.10 mm (1.4528–1.4606 in)
Valve head diameter A (exhaust) 30.40–30.60 mm (1.1968–1.2047 in)
Valve face width B (intake) 1.697 mm (0.0668 in)
Valve face width B (exhaust) 1.768 mm (0.0696 in)
A
B
A
B

ENGINE SPECIFICATIONS
2-4
Valve seat width C (intake) 0.90–1.10 mm (0.0354–0.0433 in)
Valve seat width C (exhaust) 0.90–1.10 mm (0.0354–0.0433 in)
Valve margin thickness D (intake) 1.20 mm (0.0472 in)
Valve margin thickness D (exhaust) 0.85 mm (0.0335 in)
Valve stem diameter (intake) 5.475–5.490 mm (0.2156–0.2161 in)
Limit 5.445 mm (0.2144 in)
Valve stem diameter (exhaust) 5.465–5.480 mm (0.2152–0.2157 in)
Limit 5.435 mm (0.2140 in)
Valve guide inside diameter (intake) 5.500–5.512 mm (0.2165–0.2170 in)
Limit 5.550 mm (0.2185 in)
Valve guide inside diameter (exhaust) 5.500–5.512 mm (0.2165–0.2170 in)
Limit 5.550 mm (0.2185 in)
Valve-stem-to-valve-guide clearance (intake) 0.010–0.037 mm (0.0004–0.0015 in)
Limit 0.080 mm (0.0032 in)
Valve-stem-to-valve-guide clearance (exhaust) 0.020–0.047 mm (0.0008–0.0019 in)
Limit 0.100 mm (0.0039 in)
Valve stem runout 0.010 mm (0.0004 in)
Valve spring
Free length (intake) 40.76 mm (1.60 in)
Limit 39.76 mm (1.57 in)
Free length (exhaust) 37.01 mm (1.46 in)
Limit 36.01 mm (1.42 in)
Installed length (intake) 34.78 mm (1.37 in)
Installed length (exhaust) 30.83 mm (1.21 in)
Spring rate K1 (intake) 31.90 N/mm (3.25 kgf/mm, 182.15 lbf/in)
Spring rate K2 (intake) 41.37 N/mm (4.22 kgf/mm, 236.22 lbf/in)
Spring rate K1 (exhaust) 21.46 N/mm (2.19 kgf/mm, 122.54 lbf/in)
Spring rate K2 (exhaust) 27.84 N/mm (2.84 kgf/mm, 158.97 lbf/in)
Installed compression spring force (intake) 178.00–204.00 N (18.15–20.80 kgf, 
40.01–45.86 lbf)
Installed compression spring force (exhaust) 124.00–142.00 N (12.64–14.48 kgf, 
27.88–31.92 lbf)
Spring tilt (intake) 2.5 °/1.8 mm (2.5 °/0.07 in)
Spring tilt (exhaust) 2.5 °/1.6 mm (2.5 °/0.06 in)
C
D

ENGINE SPECIFICATIONS
2-6
Oil ring
Dimensions (B  T) 1.50  2.55 mm (0.06  0.10 in)
End gap (installed) 0.20–0.50 mm (0.0079–0.0197 in)
Crankshaft
Width A 61.95–62.00 mm (2.439–2.441 in)
Runout limit C 0.030 mm (0.0012 in)
Big end side clearance D 0.150–0.450 mm (0.0059–0.0177 in)
Balancer
Balancer drive method Gear
Clutch
Clutch type Wet, multiple-disc
Clutch release method Inner push, cam push
Clutch lever free play 7.0–12.0 mm (0.28–0.47 in)
Friction plate thickness 2.92–3.08 mm (0.115–0.121 in)
Wear limit 2.85 mm (0.112 in)
Plate quantity 8 pcs
Clutch plate thickness 1.10–1.30 mm (0.043–0.051 in)
Plate quantity 7 pcs
Warpage limit 0.10 mm (0.0039 in)
Clutch spring free length 48.00 mm (1.89 in)
Minimum length 47.00 mm (1.85 in)
Spring quantity 6 pcs
Push rod bending limit 0.10 mm (0.0039 in)
Transmission
Transmission type Constant mesh 5-speed
Primary reduction system Spur gear
Primary reduction ratio 2.609 (60/23)
Final drive Chain
Secondary reduction ratio 3.769 (49/13)
Operation Left foot operation
Gear ratio
1st 1.929 (27/14)
2nd 1.533 (23/15)
3rd 1.300 (26/20)
4th 1.091 (24/22)
5th 0.952 (20/21)
B
T
CC
D
A

CAMSHAFT
5-15
c. Install the dowel pins and the camshaft
caps.
TIP
• Tighten the camshaft cap bolts in a crisscross
pattern from innermost to outer caps.
• Do not turn the camshaft when measuring the
camshaft journal-to-camshaft cap clearance.
d. Remove the camshaft caps and then mea-
sure the width of the Plastigauge® “1.”
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5. Measure:
• Camshaft journal diameter “a”
Out of specification  Replace the cam-
shaft.
Within specification  Replace the cylinder
head and the camshaft caps as a set.
EAS1SL1210CHECKING THE TIMING CHAIN AND CAM-
SHAFT SPROCKET
1. Check:
• Timing chain “1”
Damage/stiffness  Replace the timing
chain and camshaft and camshaft sprocket
as a set.
2. Check:
• Camshaft sprocket
More than 1/4 tooth wear “a”  Replace the
camshaft sprocket and the timing chain as a
set.
EAS1SL1211CHECKING THE TIMING CHAIN TENSION-
ERS
1. Check:
• Timing chain tensioner
Crack/damage  Replace.
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a. While pressing the tensioner rod lightly with
your fingers, use a thin screwdriver “1” to
wind the tensioner rod up fully clockwise.
b. When releasing the screwdriver by pressing
lightly with your fingers, make sure that the
tensioner rod will come out smoothly.
c. If not, replace the tensioner assembly.
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Camshaft cap bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Camshaft journal diameter
21.959–21.972 mm (0.8645–
0.8650 in)
T R..
1
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Camshaft sprocket
a
b1
2

VALVES AND VALVE SPRINGS
5-25
EAS1SL1220REMOVING THE VALVES
TIP
Before removing the internal parts of the cylin-
der head (e.g., valves, valve springs, valve
seats), make sure that the valves are properly
sealed.
1. Remove:
• Valve lifter “1”
• Adjusting pad “2”
TIP
• Place a cloth in the timing chain space to pre-
vent adjusting pads from falling into the crank-
case.
• Make a note of the positions of valve lifters
and adjusting pads so that they can be rein
-
stalled in their original places.
2. Check:
• Valve sealing
Leakage at the valve seat  Check the
valve face, the valve seat, and the valve seat
width.
“CHECKING THE VALVE SEATS” on page
5-27.
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a. Pour a clean solvent “a” into the intake and
exhaust ports.
b. Check that the valves are properly sealed.
TIP
Check that there are no kerosene leaks from
the valve seat “1.”
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3. Remove:
• Valve cotter “1”
TIP
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
“2” and the valve spring compressor adapter
“3.”
4. Remove:
• Valve spring retainer “1”
• Valve spring “2”
•Valve “3”
• Valve stem seal “4”
• Valve spring seat “5”
TIP
Identify the position of each part very carefully
so that it can be reinstalled in its original place.
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
1
2Valve spring compressor
90890-04019
YM-04019
Valve spring compressor adapter
22 mm
90890-040108
YM-04108
a1
a

VALVES AND VALVE SPRINGS
5-27
TIP
After replacing the valve guide, reface the valve
seat.
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3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
• Valve face
Pitting/wear  Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than
the body of the valve stem  Replace the
valve.
5. Measure:
• Valve margin thickness D “a”
Out of specification  Replace the valve.
6. Measure:
• Valve stem runout
Out of specification  Replace the valve.
TIP
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always re-
place the oil seal.
EAS1SL1222CHECKING THE VALVE SEATS
1. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
2. Check:
• Valve seat
Pitting/wear  Replace the cylinder head.
3. Measure:
• Valve seat width C “a”
Out of specification  Replace the cylinder
head.
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a. Apply Mechanic’s blueing dye (Dykem) “b”
onto the valve face.
Valve guide remover & installer
set (ø5.5)
90890-04016
Valve guide remover (5.5 mm)
YM-01122
Valve guide installer (5.5 mm)
YM-04015
Valve guide reamer (5.5 mm)
YM-01196
Valve margin thickness D (intake)
1.20 mm (0.0472 in)
Valve margin thickness D (ex-
haust)
0.85 mm (0.0335 in)
Valve stem runout
0.010 mm (0.0004 in)
Valve seat width C (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Valve seat width C (exhaust)
0.90–1.10 mm (0.0354–0.0433 in)