2019 YAMAHA YFZ450 service

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

4-23
4

Do not tamper with or attempt to open the
cylinder assembly.
 Do not subject the shock absorber assembly
to an open flame or other high heat source.
This may cause the unit to explode due to ex-
cessive gas pressure.
 Do not deform or damage the cylinder 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.
EBU29403Handlebar positionThe handlebar can be adjusted to one of two po-
sitions to suit the rider’s preference. Have a
Yamaha dealer adjust the position of the handle- bar.
1. Handlebar
1
UBW262E0.book Page 23 Tuesday, April 3, 2018 10:59 AM

8-1
8
EBU28788
PERIODIC MAINTENANCE AND ADJUSTMENT
EBU21677Periodic inspection, adjustment, and lubrication
will keep your vehicle in the safest and most effi-
cient condition possible. Safety is an obligation of
the vehicle owner and operator. The most impor-
tant points of vehicle inspection, adjustment, and
lubrication are explained on the following pages.
WARNING
EWB01842Failure to properly maintain the vehicle or per-
forming maintenance activities incorrectly may
increase your risk of injury or death during ser-
vice or while using the vehicle. If you are not fa-
miliar with vehicle service, have a Yamaha
dealer perform the service.
WARNING
EWB02563Turn off the engine when performing mainte-
nance unless otherwise specified.
A running engine has moving parts that can
catch on body parts or clothing and electri-
cal parts that can cause shocks or fires. 
Running the engine while servicing can lead
to eye injury, burns, fire, or carbon monoxide
poisoning - possibly leading to death. See
page 2-6 for more information about carbon
monoxide.

WARNING
EWB02691Brake discs, calipers, drums, and linings can
become very hot during use. To avoid possible
burns, let brake components cool before
touching them. The intervals given in the periodic maintenance
charts should be considered as a general guide
under normal riding conditions. However, DE-
PENDING ON THE WEATHER, TERRAIN, GEO-
GRAPHICAL LOCATION, AND INDIVIDUAL USE,
THE MAINTENANCE INTERVALS MAY NEED TO
BE SHORTENED.
UBW262E0.book Page 1 Tuesday, April 3, 2018 10:59 AM

8-8
8
EBU29431TIPSome maintenance items need more frequent service if you are riding in unusually wet, dusty, sandy or
muddy areas, or at full-throttle.
 Replace the fuel hose every five years and if cracked or damaged.
 Hydraulic brake service
• Regularly check and, if necessary, correct the brake fluid level.
• Every two years replace the internal components of the brake master cylinders and calipers, and
change the brake fluid.23 *Moving parts and
cables •Lubricate.
√√√√
24 *Throttle lever • Check operation.
• Check throttle lever free play, and adjust if neces-
sary.
• Lubricate cable and lever housing. √√√√√
25 *Front and rear
brake switches • Check operation and correct if necessary.
√√√√√
26 *Lights and switches • Check operation and correct if necessary.
• Adjust headlight beams. √√√√√
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 8 Tuesday, April 3, 2018 10:59 AM

8-28
8
EBU29704Adjusting the throttle lever free playPeriodically check the throttle lever free play and
adjust if necessary.1. Slide the rubber cover back.
2. Loosen the locknut. 3. To increase the throttle lever free play, turn
the throttle lever free play adjusting bolt in di-
rection (a). To decrease the throttle lever free
play, turn the adjusting bolt in direction (b).
4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24061Valve clearanceThe valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance and lu-
brication chart.EBU29602BrakesReplacement of brake components requires pro-
fessional knowledge. Brake service should be
performed by a Yamaha dealer.
WARNING
EWB02572Operating with improperly serviced or adjust-
ed brakes could lead to a loss in braking ability
and an accident.
1. Rubber cover
2. Throttle lever free play adjusting bolt
3. Locknut
4. Throttle lever free playThrottle lever free play: 2.0–4.0 mm (0.08–0.16 in)
32
4
(a)(b)
1
UBW262E0.book Page 28 Tuesday, April 3, 2018 10:59 AM

8-34
8
8. Turn in the adjusting bolt at the rear brake cal-
iper until it feels tight, then turn it out 1/8 turn
and tighten its locknut to the specified torque.
NOTICE: When tightening the locknut,
hold the adjusting bolt with a wrench so
that it does not turn together with the lock-
nut.
[ECB00522]
WARNING
EWB02091Operating with improperly serviced or adjust-
ed brakes could cause the brakes to malfunc-
tion, resulting in reduced braking
performance. This could increase the chance
of a collision or accident. After adjusting the
parking brake free play, block the rear of the
ATV off the ground and spin the rear wheels.
Check to make sure there is no brake drag. If
brake drag is noticed, perform the adjustment
again.
EBU24744Brake light switchesThe brake light, which is activated by the brake
pedal and brake lever, should come on just before
braking takes effect.
The brake light switch for the brake pedal can be
adjusted as follows, but the front brake light
switch should be adjusted by a Yamaha dealer.
Turn the rear brake light switch adjusting nut while
holding the brake light switch in place. To make
the brake light come on earlier, turn the adjusting
nut in direction (a). To make the brake light come
on later, turn the adjusting nut in direction (b).
Tightening torque:
Locknut (rear brake caliper):16 N·m (1.6 kgf·m, 12 lb·ft)1. Rear brake light switch
2. Rear brake light switch adjusting nut
1
2(a) (b)
UBW262E0.book Page 34 Tuesday, April 3, 2018 10:59 AM

8-38
8
EBU24883Lubricating the drive chainThe drive chain must be cleaned and lubricated at
the intervals specified in the periodic maintenance
and lubrication chart, otherwise it will quickly wear
out, especially when riding in dusty or wet areas.
Service the drive chain as follows.NOTICEECB00562The drive chain must be lubricated after wash-
ing the ATV or riding in the rain or wet areas. 1. Clean the drive chain with kerosene and asmall soft brush. NOTICE: To prevent dam-
aging the O-rings, do not clean the drive
chain with steam cleaners, high-pressure
washers or inappropriate solvents.
[ECB00572]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain lubricant. NOTICE: Do
not use engine oil or any other lubricants
for the drive chain, as they may contain
substances that could damage the O-
rings.
[ECB00582]
EBU24905
Checking and lubricating the cablesThe operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-1. O-rings
1
1
UBW262E0.book Page 38 Tuesday, April 3, 2018 10:59 AM

8-43
8
TIPFor parts equipped with a grease nipple, use a
grease gun. EBU2918BBatteryThis model is equipped with a 12-volt VRLA
(valve-regulated lead-acid) battery. There is no
need to check the electrolyte or to add distilled
water. However, the battery lead connections
need to be checked and tightened, and the bat-
tery terminals cleaned if corroded. If the battery
seems to have discharged, recharge it as soon as
possible.TIPWear gloves and eye protection in a ventilated
area away from sparks and open flames. Wash
hands after handling.
 It is recommended to have the battery serviced
by a Yamaha dealer.
WARNING
EWB02161Battery electrolyte is poisonous and danger-
ous, as it contains sulfuric acid, which can cau-
se severe burns. Avoid contact with skin, eyes
or clothing. Always shield your eyes when
working near batteries.
Antidote:
EXTERNAL: Flush with water.
INTERNAL: Drink large quantities of water or
milk. Follow with milk of magnesia, beaten egg
or vegetable oil. Call a physician immediately.
EYES: Flush with water for 15 minutes and get
prompt medical attention.
Batteries produce explosive gases. Keep
sparks, flame, cigarettes or other sources of
ignition away. Ventilate when charging or using
in an enclosed space.
KEEP OUT OF REACH OF CHILDREN. To remove the battery
1. Remove the seat. (See page 4-10.)
2. Remove the battery holding plate by remov- ing the bolts.
UBW262E0.book Page 43 Tuesday, April 3, 2018 10:59 AM