2021 YAMAHA YFZ450R engine

10-1
10
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
UBKD60E0.book Page 1 Wednesday, November 18, 2020 8:39 AM

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

11-1
11
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
UBKD60E0.book Page 1 Wednesday, November 18, 2020 8:39 AM

11-2
11
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
UBKD60E0.book Page 2 Wednesday, November 18, 2020 8:39 AM

11-4
11
Spring:Coil spring
Shock absorber: Gas-hydraulic damper
Wheel travel:
250 mm (9.9 in)Rear suspension:Type:Swingarm (link suspension)
Spring:
Coil spring
Shock absorber: Gas-hydraulic damper
Wheel travel: 280 mm (11.0 in)Electrical system:System voltage:12 V
Ignition system: TCI
Charging system:
AC magnetoBattery:Model:YTZ7S
Voltage, capacity:
12 V, 6.0 AhLights:Headlight:T19L, 30.0 W/30.0 W Brake/tail light:
LED
Neutral indicator light: LED
Fuel level warning light:
LED
Coolant temperature warning light: LED
Engine trouble warning light: LED
Fuses:Main fuse:20.0 AEBU30403Noise and vibration levels statement (for Eu-
rope)
The figures quoted are emission levels and are not
necessarily safe working levels. Whilst there is a
correlation between the emission and exposure
levels, this cannot be used reliably to determine
whether or not further precautions are required.
Factors that influence the actual level of exposure
of work-force include the characteristics of the
work room, the other sources of noise, etc. i.e. the
number of machines and other adjacent process-
es, and the length of time for which an operator is
exposed to the noise. Also the permissible expo-
UBKD60E0.book Page 4 Wednesday, November 18, 2020 8:39 AM

12-1
12
INDEX
AAccessories and loading ................................................ 7-5
Air filter element, cleaning ........................................... 9-22BBattery ......................................................................... 9-43
Brake and clutch levers, checking and lubricating ...... 9-39
Brake fluid, changing ................................................... 9-31
Brake fluid level, checking ........................................... 9-30
Brake lever ..................................................................... 5-5
Brake lever free play, checking the front ..................... 9-32
Brake light switches ..................................................... 9-34
Brake pads, checking the front and rear ..................... 9-29
Brake pedal .................................................................... 5-6
Brake pedal, checking and lubricating ........................ 9-40
Brake pedal height, checking ...................................... 9-32
Brakes .......................................................................... 9-28
Brakes, front and rear .................................................... 6-4
Brake/tail light .............................................................. 9-49CCables, checking and lubricating ................................ 9-38
Chassis fasteners .......................................................... 6-7
Cleaning ....................................................................... 10-1
Clutch lever .................................................................... 5-5
Clutch lever free play, adjusting .................................. 9-35
Coolant .................................................................6-4, 9-20
Coolant, changing ........................................................ 9-22
Coolant temperature warning light ................................ 5-2
Cowling and panels, removing and installing .............. 9-10
DDrive chain ..................................................................... 6-5
Drive chain, lubricating ................................................ 9-38
Drive chain slack .......................................................... 9-36EEngine break-in .............................................................. 7-4
Engine oil ....................................................................... 6-4
Engine oil and oil filter element .................................... 9-14
Engine, start ................................................................... 7-1
Engine stop switch ........................................................ 5-3
Engine trouble warning light .......................................... 5-2FFuel ......................................................................... 5-9, 6-4
Fuel level warning light .................................................. 5-2
Fuel tank cap ................................................................. 5-8
Fuse, replacing ............................................................ 9-46HHandlebar position, adjusting ...................................... 5-23
Handlebar switches ....................................................... 5-3
Headlight beam, adjusting ........................................... 9-49
Headlight bulb, replacing ............................................. 9-46IIdentification numbers ................................................... 1-1
Indicator light and warning lights ................................... 5-1
Instruments, lights and switches ................................... 6-7LLabel locations ............................................................... 2-1
Light switch ................................................................... 5-3
UBKD60E0.book Page 1 Wednesday, November 18, 2020 8:39 AM