2016 YAMAHA YZ450F fuel pump

STARTING AND BREAK-IN
1-21
EASB111040
STARTING AND BREAK-IN
EASB111041FUEL
Always use the recommended fuel as stated
below. Also, be sure to use new gasoline the
day of a race.
ECA
NOTICE
Use only unleaded gasoline. The use of
leaded gasoline will cause severe damage
to the engine internal parts such as valves,
piston rings, and exhaust system, etc.
TIP
Your Yamaha engine has been designed to use
premium unleaded gasoline with a pump oc-
tane number [(R+M)/2] of 91 or higher, or a re-
search octane number of 95 or higher. If
knocking (or pinging) occurs, use a gasoline of
a different brand.
EWA
WARNING
• For refueling, be sure to stop the engine
and use enough care not to spill any fuel.
Also be sure to avoid refueling close to a
fire.
• Refuel after the engine, exhaust pipe, etc.
have cooled off.
Gasohol (For USA and Canada)
There are two types of gasohol: gasohol con-
taining ethanol and that containing methanol.
Gasohol containing ethanol can be used if the
ethanol content does not exceed 10%. Gasohol
containing methanol is not recommended by
Yamaha because it can cause damage to the
fuel system or vehicle performance problems.
EASB111042STARTING A COLD ENGINE
1. Press the shift pedal to neutral.
2. Pull the starter knob/idle screw “1” to its full
length.
TIP
When the ambient temperature is 15°C (59°F)
or below, use the starter knob/idle screw.
3. Push down the kickstarter lever lightly until
resistance is felt.
4. Fully close the throttle, and push down the
kickstarter lever in a stroke.
5. Immediately release the kickstarter lever.
EWA
WARNING
Do not open the throttle at the moment
when you kick the kickstarter lever, be-
cause this may kick back
TIP
If it fails to start, fully open the throttle grip and
give 10 to 20 slow kicks to clear the engine of
the rich air-fuel mixture retained in it.
6. When the engine starts running, warm this
up one or two minutes at a steady speed (of
3000 to 5000 r/min), and then return the
starter knob/idle screw to its original posi-
tion.
EWA
WARNING
Since exhaust gas contains harmful ingre-
dients, do not start or warm it up at an ill-
ventilated place or a closed narrow place. Recommended fuel
Premium unleaded gasoline
only
Fuel tank capacity
7.5 L (1.98 US gal, 1.65 Imp.gal)
1

TORQUE-CHECK POINTS
1-24
EASB111047
TORQUE-CHECK POINTS
Frame construction Frame to rear frame
Frame to engine protector
Combined seat and fuel tank Fuel tank to frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Seat Seat to frame
Steering Steering stem to handlebar Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Suspension Front Steering stem to front fork Front fork to upper bracket
Front fork to lower bracket
Rear Link Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Mounting of rear shock absorber Rear shock absorber and frame
Mounting of swingarm Tightening of pivot shaft
Wheel (s) Mounting of wheel Front Tightening of wheel axle
Tightening of axle holder
Tightening of spoke nipple
Rear Tightening of wheel axle
Wheel to rear wheel sprocket
Tightening of spoke nipple
Brake(s) Front Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handle-
bar
Tightening of bleed screw
Tightening of brake hose holder
Rear Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel system Fuel pump to fuel tank

ENGINE SPECIFICATIONS
2-2
EASB111052
ENGINE SPECIFICATIONS
Engine
Engine type Liquid cooled 4-stroke, DOHC
Displacement 450 cm
3
Cylinder arrangement Single cylinder
Bore  stroke 97.0  60.8 mm (3.8  2.4 in)
Compression ratio 12.5:1
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-40, SAE 10W-50, SAE 15W-40,
SAE 20W-40 or SAE 20W-50
Recommended engine 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 (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 valve opening pressure 108–137 kPa (1.08–1.37 kg/cm
2, 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(s)
Manufacturer/model NGK/CR8E
Spark plug gap 0.7–0.8 mm (0.028–0.031 in)

ENGINE SPECIFICATIONS
2-5
Crankshaft
Crank assembly width 61.95–62.00 mm (2.439–2.441 in)
Runout limit 0.030 mm (0.0012 in)
Big end side clearance 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 1.50–1.70 mm (0.059–0.067 in)
Plate quantity 7 pcs
Warpage limit 0.10 mm (0.0039 in)
Clutch spring free length 48.00 mm (1.89 in)
Limit 45.60 mm (1.80 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 3.692 (48/13)
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)
Main axle runout limit 0.08 mm (0.0032 in)
Drive axle runout limit 0.08 mm (0.0032 in)
Shifting mechanism
Shift mechanism type Shift drum and guide bar
Shift fork guide bar bending limit 0.050 mm (0.0020 in)
Shift fork thickness 4.85 mm (0.1909 in)
Decompression device
Device type Auto decomp
Air filter
Air filter element Wet element
Air filter oil grade Foam air-filter oil
Fuel pump
Pump type Electrical
Fuel injector
Model/quantity 1010/1
Resistance 12.0 

TIGHTENING TORQUES
2-19
TIP
1. First, tighten the lower ring nut approximately 38 Nm (3.8 m·kgf, 27 ft·lbf) by using the steering nut
wrench, then loosen the lower ring nut one turn.
2. Retighten the lower ring nut 7 Nm (0.7 m·kgf, 5.1 ft·lbf).Drive chain tensioner bolt (lower
side)M8 1 16 Nm (1.6 m·kgf, 12 ft·lbf)
Drive chain support bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Drive chain support nut M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Drive chain guide bolt M5 3 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Rear frame and left cover bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bolt (front side) M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bolt (rear side) M6 1 9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Fuel tank bracket bolt (front side) M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bracket bolt (rear side) M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel pump bolt M5 6 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Fuel inlet pipe screw M5 2 3.4 Nm (0.34 m·kgf, 2.5 ft·lbf)
Fuel tank cap cover bolt M6 2 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Seat set bracket and fuel tank screw M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Seat bolt M8 2 22 Nm (2.2 m·kgf, 16 ft·lbf)
Left side cover bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Right side cover bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Frame and air scoop bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank and air scoop bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Radiator guard and air scoop bolt M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Front fender bolt M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Rear fender bolt (front side) M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Rear fender bolt (rear side) M6 2 16 Nm (1.6 m·kgf, 12 ft·lbf)
Mud flap screw — 2 1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
Number plate bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks

CABLE ROUTING DIAGRAM
2-34
1. Bracket
2. Condenser
3. Coolant temperature sensor
4. Coupler cover
5. Intake air pressure sensor coupler
6. Intake air temperature sensor coupler
7. Radiator hose
8. Radiator breather hose
9. Joint coupler
10. Plate
11. Tension arm
12. Throttle position sensor lead
13. Ground lead
14. Throttle position sensor coupler
15. Radiator breather hose
16. Cylinder head breather hose
17. Engine guard
18. Crankcase
19. Fuel pump coupler
20. Fuel hose
21. Condenser lead
22. Fuel pump lead
23. Condenser coupler
24. Ground lead terminal
25. Fuel tank
26. Damper
27. Rear frame
28. Main harness
A. Insert the condenser into the bracket as far as it
will go.
B. Attach the coupler cover to the coolant tempera-
ture sensor coupler.
C. Pass the radiator breather hose to the inside of
the radiator hose (the side of the vehicle).
D. Insert and fix the joint coupler to the plate. After
fixing it, attach the cover.
E. Pass the throttle position sensor lead to the out-
side of the tension arm (the outside of the vehi-
cle).
F. After connecting the throttle position sensor cou-
pler, attach the cover.
G. Pass the radiator breather hose to the outside of
the tension arm and the throttle position sensor
lead (the outside of the vehicle), and to the inside
of the radiator hose (the side of the vehicle).
H. Pass the protector of the cylinder head breather
hose until it touches the holder.
I. Pass the cylinder head breather hose between
the engine guard and the crankcase.
J. Install the end of the cylinder head breather hose
with it facing downward.
K. After connecting the fuel pump coupler, attach
the coupler cover.
L. 55 mm (2.17 in) (seat load receiver)
M. Clamp the fuel hose and the fuel pump lead by
the holder. Make sure that the painted part on the
fuel hose is clamped, and face the lock on the
clamp toward the rear top of the vehicle.
N. Do not install the plastic locking tie to the seat
load receiver.
O. Make the lock on the plastic locking tie face the
front of the vehicle, and make the end face the
bottom of the vehicle. Do not cut the end.
P. Install the ground lead terminal between the plate
and the bolt.
Q. Detent
R. Fix the ground lead terminal to the detent in the
plate. For the ground lead terminal, either side
will do.S. Insert the projection on the plastic locking tie into
the hole in the rear frame.
T. Clamp the painted part on the fuel hose by the
plastic clamp. Make the lock on the plastic clamp
face the bottom of the vehicle, and cut the end.

MAINTENANCE INTERVALS
3-4
FUEL TANK, FUEL
PUMP
Inspect
FUEL HOSE
Inspect
Replace Every four years
FRONT FORK LEG
(S)
Clean Dust seal
Inspect and adjust
Replace oil
Replace oil seal
Clean and grease
oil seals and dust
sealsLithium-soap-based grease
PROTECTOR
GUIDE
Replace
REAR SHOCK AB-
SORBER
Inspect and adjust
Lubricate(After
rain
ride)Grease pillow balls and bear-
ings.
Retighten Check for tightening torques.ITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

ENGINE
3-16
d. Install the oil strainer.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
6. Install:
• Engine oil drain bolt
• Drain bolt
7. Pour the specified amount of engine oil into
the oil filler cap hole.
8. Install:
• Oil filler cap
9. Check:
• Oil level
Refer to “CHECKING THE ENGINE OIL
LEVEL” on page 3-14.
10.Check:
• Engine oil pressure
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly loosen the oil pressure check bolt
“1”.
EWA
WARNING
When the engine is started with the check
bolt removed, oil will spout; therefore, al-
ways loosen it before the checkup.
Start the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt.
EWA
WARNING
Always keep the engine idling speed during
the checkup without increasing the engine
speed.
ECA
NOTICE
If no engine oil seeps out after one minute,
immediately turn the engine off so it will not
seize.
b. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
c. Check the oil pressure again.
d. Tighten the oil pressure check bolt.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲EASB111086ADJUSTING THE ENGINE IDLING SPEED
TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer.
If the idling speed is low, turn the starter knob/
idle screw a few clicks counterclockwise to in-
crease the speed before the adjustment.
• Before adjusting the engine idling speed,
make sure that the air filter element is not
clogged, the engine compression is proper,
and the throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob/idle screw pushed in completely. Oil strainer bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Drain bolt
20 Nm (2.0 m·kgf, 14 ft·lbf)
Engine oil quantity
With oil filter element replace-
ment
0.69 L (0.73 US qt, 0.61 Imp.qt)
Quantity (disassembled)
0.95 L (1.00 US qt, 0.84 Imp.qt)
1
2New
T R..
New
T R..
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1
T R..