2021 YAMAHA YFZ450R Owners Manual

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9
EBU27696Troubleshooting chartsStarting problems or poor engine performance
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.There is no fuel.
Check the battery.
Supply fuel.
The engine does not start.
Check the battery.
Operate the electric starter.4. Compression
There is compression.
There is no compression.
The engine does not start.
Have a Yamaha dealer check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug. Have a Yamaha dealer check the ATV.
The engine does not start.
Check the compression.
DryWet
Operate the electric starter.
Have a Yamaha dealer check the ATV.
The engine does not start.
Check the ignition.
Operate the electric starter.2. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and have a Yamaha dealer charge
the battery if necessary.
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9Engine overheating
WARNING
EWB02291Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap. TIP
Tap water can be used in an emergency. Change to the recommended coolant as soon as possible.
 The engine will tend to overheat if the radiator is caked with mud, or if the ATV is overloaded. Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See TIP.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
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EBU25861
CLEANING AND STORAGE
EBU25903CleaningFrequent, thorough cleaning of your ATV will not
only enhance its appearance but will improve its
general performance and extend the useful life of
many components.1. Before cleaning the ATV: a. Block off the end of the exhaust pipe toprevent water entry. A plastic bag and
strong rubber band may be used.
b. Make sure the spark plug and all filler caps are properly installed.
2. If the engine case is excessively greasy, apply degreaser with a paint brush. Do not apply
degreaser to the chain, sprockets or wheel
axles.
3. Rinse the dirt and degreaser off with a garden hose. Use only enough pressure to do the
job. WARNING! Wet brakes may have re-
duced stopping ability, increasing the
chance of an accident. Test the brakes af-
ter washing. Apply the brakes several
times at slow speeds to let friction dry out
the linings.
[EWB02312]
NOTICE: Excessive wa- ter pressure may cause water seepage
and deterioration of wheel bearings,
brakes, transmission seals and electrical
devices. Many expensive repair bills have
resulted from improper high-pressure de-
tergent applications such as those avail-
able in coin-operated car washers.
[ECB00712]
4. Once most of the dirt has been hosed off,
wash all surfaces with warm water and mild,
detergent-type soap. An old toothbrush or
bottle brush is handy for hard-to-reach plac-
es.
5. Rinse the ATV off immediately with clean wa- ter and dry all surfaces with a chamois, clean
towel or soft absorbing cloth.
6. Dry the chain and lubricate it to prevent it from rusting.
7. Clean the seat with a vinyl upholstery cleaner to keep the cover pliable and glossy.
8. Automotive type wax may be applied to all painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
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10-2
10abrasives which may mar the paint or protec-
tive finish. When finished cleaning, start the
engine and let it idle for several minutes.
EBU27264StorageShort-term
Always store your ATV in a cool, dry place and, if
necessary, protect it against dust with a porous
cover.
NOTICE: Storing the ATV in a poorly ven-
tilated room or covering it with a tarp while it is
still wet, will allow water and humidity to seep
in and cause rust. To prevent corrosion, avoid
damp cellars, stables (because of the presence
of ammonia) and areas where strong chemi-
cals are stored.
[ECB00722]
Long-term
Before storing your ATV for several months: 1. Make any necessary repairs and perform all outstanding maintenance.
2. Follow all the instructions in the Cleaning sec- tion of this chapter. 3. Fill up the fuel tank and add fuel stabilizer (Fu-
el Med Rx if available), and then run the en-
gine for 5 minutes to distribute the treated
fuel.
4. Perform the following steps to protect the en- gine from internal corrosion.a. Remove the spark plug cap and spark plug.
b. Pour a teaspoonful of engine oil into the spark plug bore.
c. Install the spark plug cap onto the spark plug, and then place the spark plug on the
cylinder head so that the electrodes are
grounded. (This will limit sparking during
the next step.)
d. Turn the engine over several times with the starter. (This will coat the cylinder wall
with oil.)
e. Remove the spark plug cap from the spark plug, and then install the spark plug and
the spark plug cap.
5. Lubricate all control cables and the pivoting points of all levers and pedals.
Specified amount:
7.5 ml per liter of fuel (1 oz per gallon)UBKD60E0.book Page 2 Wednesday, November 18, 2020 8:39 AM

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10
6. Put the frame on stands or blocks to raise all
wheels off the ground. (Alternatively, turn the
wheels each month to prevent the tires from
degrading in one spot.)
7. Cover the muffler outlet with a plastic bag to prevent moisture from entering it.
8. Remove the battery and fully charge it. (See page 9-43.)
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EBU25964
SPECIFICATIONS
Dimensions:Overall length:1795 mm (70.7 in)
Overall width: 1240 mm (48.8 in)
Overall height:
1065 mm (41.9 in)
Seat height: 810 mm (31.9 in)
Wheelbase: 1270 mm (50.0 in)
Ground clearance:
235 mm (9.3 in)
Minimum turning radius: 3.6 m (11.81 ft)
Maximum water depth: 35 cm (14 in)Weight:Curb weight:184.0 kg (406 lb)Loading:Maximum load:
100.0 kg (220 lb)
(Total weight of rider, cargo, accessories, and tongue)Noise and vibration level:Noise level (77/311/EEC):85.9 dB(A) at 3750 r/min Uncertainty of measurement:
3.0 dB(A)
A-weighted sound power level: 99.0 dB(A) at 3750 r/min
Uncertainty of measurement: 3.0 dB(A)
Vibration on seat (EN1032, ISO5008):
Will not exceed 0.5 m/s²
Uncertainty of measurement: 0.1 m/s²
Vibration on handle (EN1032, ISO5008): 2.9 m/s²
Uncertainty of measurement:
0.8 m/s²
Engine:Combustion cycle:4-stroke
Cooling system:
Liquid cooled
Valve train: DOHC
Number of cylinders: Single cylinder
Displacement:
449 cm³
Bore × stroke:
95.0 × 63.4 mm (3.74 × 2.50 in)
Compression ratio: 11.8 : 1
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Starting system:Electric starter
Lubrication system: Dry sumpEngine oil:Recommended brand:
SAE viscosity grades:
5W-30, 10W-30, 10W-40, 15W-40, 20W-40, 20W-50
Recommended engine oil grade: API service SG type or higher, JASO standard MA
Quantity: Oil change:1.40 L (1.48 US qt, 1.23 Imp.qt) With oil filter removal:
1.45 L (1.53 US qt, 1.28 Imp.qt)
Coolant quantity:Radiator (including all routes):
1.25 L (1.32 US qt, 1.10 Imp.qt)
Coolant reservoir (up to the maximum level mark): 0.25 L (0.26 US qt, 0.22 Imp.qt)Air filter:Air filter element:
Wet element
Air filter oil grade: Foam air-filter oilFuel:Recommended fuel:
Premium unleaded gasoline (Gasohol [E10] acceptable)
Minimum research octane: 97
Fuel tank capacity: 10 L (2.6 US gal, 2.2 Imp.gal)
Fuel reserve amount:
3.4 L (0.90 US gal, 0.75 Imp.gal)Throttle body:ID mark:1TD1Spark plug (s):Manufacturer/model:NGK/CR8E
Spark plug gap: 0.7–0.8 mm (0.028–0.031 in)
0 10 30 50 70 90 110 130 F
–20 –10 0 10 20 30 40 50 CSAE 5W-30
SAE 10W-30
SAE 10W-40
SAE 15W-40
SAE 20W-40SAE 20W-50
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Drivetrain:Primary reduction ratio:2.652 (61/23)
Secondary reduction ratio:
2.714 (38/14)
Final drive: Chain
Clutch type: Wet, multiple-disc
Transmission type:
5-speed
Gear ratio: 1st:
2.500 (35/14)
2nd: 2.000 (30/15)
3rd: 1.632 (31/19)
4th:
1.333 (28/21)
5th: 1.095 (23/21)Front tire:Size:
AT21 x 7R10
Manufacturer/model: MAXXIS/MS21Rear tire:Size:
AT20 x 10R9
Manufacturer/model: MAXXIS/MS22
Tire air pressure (measured on cold tires):Vehicle load:0.0–100.0 kg (0–220 lb)
Recommended:
Front: 35.0 kPa (0.350 kgf/cm², 5.0 psi)
Rear:
35.0 kPa (0.350 kgf/cm², 5.0 psi)
Minimum: Front:
32.0 kPa (0.320 kgf/cm², 4.6 psi)
Rear: 32.0 kPa (0.320 kgf/cm², 4.6 psi)Front wheel:Rim size:
10 X 5.5ATRear wheel:Rim size:9 X 8.0ATFront brake:Type:Hydraulic disc brakeRear brake:Type:
Hydraulic disc brakeBrake fluid:Specified brake fluid:DOT 4Front suspension:Type:Double wishbone
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