2018 YAMAHA YFZ450R compression ratio

4-11
4
To install the seat
Insert the projections on the front of the seat into
the seat holders and push down on the seat at the
rear. Make sure that the seat is securely fitted.
EBU30052Front shock absorbersThese shock absorber assemblies are equipped
with a spring preload adjusting nut, a rebound
damping force adjusting screw, with a compres-
sion damping force adjusting bolt (for fast com- pression damping), and a compression damping
force adjusting screw (for slow compression
damping).
WARNING
EWB02492
Suspension components become hot during
operation. Never touch the compression
damping force adjusting bolt and screw, the
rebound damping force adjusting screw or
the oil reservoir with your bare hand or skin
until suspension components have cooled.
 Always adjust the shock absorber assem-
blies on the left and right side to the same
setting. Uneven adjustment can cause poor
handling and loss of stability, which could
lead to an accident. NOTICEECB00091Never turn an adjusting mechanism beyond
the minimum and maximum settings. TIPAlthough the total number of clicks or turns of a
damping force adjusting mechanism may not ex-
actly match the following specifications due to
1. Projection
2. Seat holder
1
2
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4-16
4
Do not dispose of a damaged or worn out
shock absorber assembly yourself. Take the
shock absorber assembly to a Yamaha deal-
er for any service.
EBU30143Rear shock absorbersThis shock absorber assembly is equipped with a
spring preload adjusting nut, a rebound damping
force adjusting screw, a compression damping
force adjusting bolt (for fast compression damp-
ing), and a compression damping force adjusting
screw (for slow compression damping).
WARNING
EWB02681Suspension components become hot during
operation. Never touch the compression
damping force adjusting bolt and screw, the
rebound damping force adjusting screw or the
oil reservoir with your bare hand or skin until
the suspension components have cooled. NOTICEECB00091Never turn an adjusting mechanism beyond
the minimum and maximum settings.
TIPAlthough the total number of clicks or turns of a
damping force adjusting mechanism may not ex-
actly match the following specifications due to
small differences in production, the actual number
of clicks or turns always represents the entire ad-
justing range. To obtain a precise adjustment, it
would be advisable to check the number of clicks
or turns of each damping force adjusting mecha-
nism and to modify the specifications as neces-
sary. Spring preload
1. Remove the cowling. (See page 8-10.)
2. Remove the clip from the hose holder, re- move the bolt, and then move the blow-by
gas chamber away from the vehicle.
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8-50
8
EBU25741TroubleshootingAlthough Yamaha ATVs receive a thorough in-
spection before shipment from the factory, trouble
may occur during operation. Any problem in the
fuel, compression, or ignition systems, for exam-
ple, can cause poor starting and loss of power.
The following troubleshooting charts represent
quick and easy procedures for checking these vi-
tal systems yourself. However, should your ATV
require any repair, take it to a Yamaha dealer,
whose skilled technicians have the necessary
tools, experience, and know-how to service the
ATV properly.
Use only genuine Yamaha replacement parts. Im-
itation parts may look like Yamaha parts, but they
are often inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWB02281Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.
Tightening torques:Front wheel nut:45 N·m (4.5 kgf·m, 33 lb·ft)
Rear wheel nut: 45 N·m (4.5 kgf·m, 33 lb·ft)
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10-1
10
EBU25962
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: 3600 mm (142 in)Weight:Curb weight:
184.0 kg (406 lb)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): Will not exceed 2.5 m/s²
Uncertainty of measurement:
0.8 m/s²
Engine:Engine type:Liquid cooled 4-stroke, DOHC
Cylinder arrangement:
Single cylinder
Displacement: 449 cm³
Bore × stroke:
95.0 × 63.4 mm (3.74 × 2.50 in)
Compression ratio:
11.8 : 1
Starting system: Electric starter
Lubrication system: Dry sumpEngine oil:Recommended brand:YAMALUBE
UBW261E0.book Page 1 Friday, May 26, 2017 9:38 AM