2019 YAMAHA YFZ450 suspension

2-5
2
4. Once immediate safety hazards are con-
firmed not to exist, you may remove your hel-
met to more closely inspect your vehicle.
Check for external signs of wear, broken
parts, fluid leaks, cracks in the frame, sus-
pension damage, wheel damage, and so on.
Fuel, oil, and coolant usually give off a notice-
able odor.
5. If your vehicle will not restart or if it is unsafe to ride, then turn off all vehicle systems (en-
gine stop switch, main switch, and fuel cock),
and then signal or go for help.
Aftermarket Parts, Accessories, and Modifica-
tions
While you may find aftermarket products similar in
design and quality to genuine Yamaha accesso-
ries, recognize that some aftermarket accessories
or modifications are not suitable because of po-
tential safety hazards to you or others. Installing
aftermarket products or having other modifica-
tions performed to your vehicle that change any of
the vehicle’s design or operation characteristics
can put you and others at greater risk of serious
injury or death. You are responsible for injuries re-
lated to changes in the vehicle. Keep the following guidelines in mind, as well as those found in the
Loading section (page 6-6) when mounting acces-
sories.

Never install accessories that would impair the
performance of your ATV. Carefully inspect the
accessory before using it to make sure that it
does not in any way reduce ground clearance,
limit suspension travel, steering travel or control
operation.
 Accessories fitted to the ATV can create insta-
bility due to improper weight distribution.
 Bulky or large accessories may seriously affect
the stability of the ATV.
 Certain accessories can displace the operator
from his or her normal riding position. This im-
proper position limits the freedom of movement
of the operator and may limit control ability,
therefore, such accessories are not recom-
mended.
 Use caution when adding electrical accesso-
ries. If electrical accessories exceed the capac-
ity of the ATV’s electrical system, an electric
failure could result, which could cause a dan-
gerous loss of lights or engine power. Also, the
battery tends to discharge more quickly if elec-
trical accessories are added.
UBW262E0.book Page 5 Tuesday, April 3, 2018 10:59 AM

4-11
4
To install the seat
Insert the projections on the front of the seat into
the seat holders, and then push down on the seat
at the rear to lock it in place. Make sure that the
seat is securely fitted.
EBU30054Front shock absorbers The shock absorber spring preload, rebound
damping force, and compression damping force
(fast and slow compression damping) can be ad-
justed.
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. Notes on adjusting the suspension
A special wrench can be obtained at a Yamaha
dealer to make the spring preload adjustment.
 When adjusting the damping force settings, turn
the adjuster in direction (a) until it stops, and
then count the turns or clicks in direction (b).
 Although a damping force adjuster may turn or
click beyond the stated minimum settings, such
adjustments are ineffective and may damage
the suspension.
1. Projection
2. Seat holder
1
2
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4-12
4
NOTICEECB00091Never turn an adjusting mechanism beyond
the minimum and maximum settings. Spring preload1. Loosen the locknut.
2. Turn the spring preload adjusting nut in direc- tion (a) to increase the spring preload and
thereby harden the suspension. Turn in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
TIPThe spring preload setting is determined by
measuring distance A, shown in the illustration.
 The shorter distance A is, the greater the spring
preload. The longer distance A is, the lesser the
spring preload.
 Each complete turn of the adjusting nut chang-
es distance A by 1.5 mm (0.06 in).
1. Locknut
2. Spring preload adjusting nut
3. Special wrench
(a)
(b) 2 1
3
Spring preload setting: Minimum (soft):Distance A = 302.5 mm (11.91 in)
Standard: Distance A = 293.0 mm (11.54 in)
Maximum (hard): Distance A = 282.5 mm (11.12 in)
UBW262E0.book Page 12 Tuesday, April 3, 2018 10:59 AM

4-15
4
WARNING
EWB00411These shock absorber assemblies contain
highly pressurized nitrogen gas. Read and un-
derstand the following information before han-
dling the shock absorber assemblies.
Do not tamper with or attempt to open the
cylinder assemblies.
 Do not subject the shock absorber assem-
blies to an open flame or other high heat
source. This may cause the unit to explode
due to excessive gas pressure.
 Do not deform or damage the cylinders in
any way. Cylinder damage will result in poor
damping performance.
 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.
EBU30145Rear shock absorbersThe shock absorber spring preload, rebound
damping force, and compression damping force
(fast and slow compression damping) can be ad-
justed.
WARNING
EWB02681Suspension components become hot during
operation. Never touch the compression
damping force adjusting bolt and screw, the
1. Slow compression damping force adjusting screwSlow compression damping force settings:
Minimum (soft):20 click(s) in direction (b)
Standard: 7 click(s) in direction (b)
Maximum (hard): 1 click(s) in direction (b)
(a)
(b)
1
UBW262E0.book Page 15 Tuesday, April 3, 2018 10:59 AM

4-16
4rebound damping force adjusting screw or the
oil reservoir with your bare hand or skin until
the suspension components have cooled.
Notes on adjusting the suspension

A special wrench can be obtained at a Yamaha
dealer to make the spring preload adjustment.
 When adjusting the damping force settings, turn
the adjuster in direction (a) until it stops, and
then count the turns or clicks in direction (b).
 Although a damping force adjuster may turn or
click beyond the stated minimum settings, such
adjustments are ineffective and may damage
the suspension.NOTICEECB00091Never turn an adjusting mechanism beyond
the minimum and maximum settings. 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. 3. Loosen the clamp screw at the air filter case
side.
1. Hose holder
2. Clip
3. Bolt
4. Blow-by gas chamber
2 3
4
1
UBW262E0.book Page 16 Tuesday, April 3, 2018 10:59 AM

4-18
46. Disconnect the coupler. 7. Loosen the clamp screw at the throttle body
side, and then disconnect the air intake duct
from the throttle body.
8. Loosen the locknut.
9. Turn the spring preload adjusting nut in direc- tion (a) to increase the spring preload and
thereby harden the suspension. Turn in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
1. Air filter case
2. Bolt
1. Coupler
1 2
2
1
1. Clamp screw
2. Air intake duct
1
2
UBW262E0.book Page 18 Tuesday, April 3, 2018 10:59 AM

8-7
8
14*Drive chain roller • Check for wear and replace if necessary. √√√
15 *Chassis fasteners • Make sure that all nuts, bolts, and screws are
properly tightened. √√√√√
16 *Shock absorber as-
semblies • Check operation and correct if necessary.
• Check for oil leakage and replace if necessary.
√√√
17 *Rear suspension re-
lay arm and con-
necting arm
pivoting points • Check operation and correct if necessary.
√√√√
18 *Steering shaft • Lubricate with lithium-soap-based grease. √√√
19 *Steering system • Check operation and repair or replace if dam-
aged.
• Check toe-in and adjust if necessary. √√√√√
20 Engine oil • Change.
• Check ATV for oil leakage, and correct if neces-
sary. √ √√√
21 Engine oil filter ele-
ment
• Replace.
√√√
22 *Cooling system • Check coolant level and ATV for coolant leakage,
and correct if necessary. √√√√√
• Replace coolant. Every 2 years
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev-
er comes first month136612
km (mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320UBW262E0.book Page 7 Tuesday, April 3, 2018 10:59 AM

10-3
10
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/MS22Tire 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
Spring:
Coil spring
UBW262E0.book Page 3 Tuesday, April 3, 2018 10:59 AM