maintenance YAMAHA YFM90 2017 Owner's Manual

8-21
8
4. Tighten the locknut.
5. Slide the rubber covers to their original posi-
tions.
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. EBU34511Checking the front and rear brake
shoesThe front and rear brake shoes must be checked
for wear at the intervals specified in the periodic
maintenance and lubrication chart. Without disas-
sembling the brake, this can be performed by
checking the position of the brake lever free play
adjusting bolts or nut.
Front brakes
To check front brake shoe wear, check the posi-
tion of the adjusting bolts. If a bolt extends more
than 12 mm (0.47 in) from its locknut, the brake
shoes need to be replaced.
1. Rubber cover
2. Throttle lever free play adjusting nut
3. Locknut
4. Throttle lever free play
1
3
2
1
4
(b)
(a)
UBD361E0.book Page 21 Monday, January 25, 2016 10:53 AM

8-22
8Rear brake
To check rear brake shoe wear, check the position
of the adjusting nut. If the nut is more than 18 mm
(0.71 in) from the end of the bolt, the brake shoes
need to be replaced.
EBU24332Adjusting the front brake lever free
playThe front brake lever free play must be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart.
The brake lever free play should measure 20.0–
25.0 mm (0.79–0.98 in) as shown. If the free play is
incorrect, adjust it as follows.
1. Upper adjusting bolt
2. Lower adjusting bolt
3. No more than 12 mm (0.47 in)
3
21
1. Rear brake lever free play adjusting nut
2. Bolt
3. No more than 18 mm (0.71 in)
12
3
UBD361E0.book Page 22 Monday, January 25, 2016 10:53 AM

8-24
86. Tighten the upper locknut.
TIPAfter adjusting the brake lever free play, check the
front brake shoes for wear. EBU33782Adjusting the rear brake lever free playThe rear brake lever free play must be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart. The brake lever free play should measure 30.0–
40.0 mm (1.18–1.57 in) as shown. If the free play is
incorrect, adjust it as follows.
Turn the adjusting nut in direction (a) to increase
the brake lever free play, and in direction (b) to de-
crease it.1. Cable joint1
aa´
a=a´
1. Rear brake lever free play
1
UBD361E0.book Page 24 Monday, January 25, 2016 10:53 AM

8-27
8
4. To tighten the drive chain, turn the drive chain
slack adjusting nut in direction (a). To loosen
the drive chain, turn the adjusting nut in direc-
tion (b) and push the rear wheels forward.
NOTICE: Improper drive chain slack will
overload the engine as well as other vital
parts of the ATV and can lead to drive
chain slippage or breakage. To prevent
this from occurring, keep the drive chain
slack within the specified limits.
[ECB00543]
5. Tighten the locknut, and then the bolts and nuts to their specified torques. 6. Adjust the rear brake lever free play. (See
page 8-24.)
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. Drive chain slack adjusting nut
2. Locknut
1
2
(a)
(b)
Tightening torques:Locknut:22 Nm (2.2 m·kgf, 16 ft·lbf)
Bolt: 45 Nm (4.5 m·kgf, 33 ft·lbf)
Nut: 54 Nm (5.4 m·kgf, 39 ft·lbf)
UBD361E0.book Page 27 Monday, January 25, 2016 10:53 AM

8-29
8
do not work smoothly, you could be unable
to control the ATV, which could lead to an
accident or collision.
EBU28703Checking and lubricating the front and
rear brake leversThe operation of the front and rear brake levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
Front brake lever
Rear brake lever
EBU24964Checking the wheel hub bearingsThe front and rear wheel hub bearings must be
checked at the intervals specified in the periodic
maintenance and lubrication chart. If there is play
in a wheel hub or if a wheel does not turn smooth-
ly, have a Yamaha dealer check the wheel hub
bearings.
Recommended lubricant:
Lithium-soap-based grease
UBD361E0.book Page 29 Monday, January 25, 2016 10:53 AM

8-30
8
EBU28824Lubricating the front knuckle pivotsThe front knuckle pivots must be lubricated at the
intervals specified in the periodic maintenance
and lubrication chart.TIPFor parts equipped with a grease nipple, use a
grease gun.
EBU25094Lubricating the steering shaftThe steering shaft must be lubricated by a
Yamaha dealer at the intervals specified in the pe- riodic maintenance and lubrication chart.TIPFor parts equipped with a grease nipple, use a
grease gun.
Recommended lubricant: Lithium-soap-based grease
1. Grease nippleRecommended lubricant:Lithium-soap-based grease
1
UBD361E0.book Page 30 Monday, January 25, 2016 10:53 AM

12-1
12
INDEX
AAccessories and loading ................................................ 6-6
Air filter element, cleaning ............................................ 8-15BBattery .......................................................................... 8-31
Brake lever free play, adjusting the front ..................... 8-22
Brake lever free play (rear), adjusting ........................... 8-24
Brake lever, front ............................................................ 4-4
Brake lever, rear ............................................................. 4-5
Brake levers, checking and lubricating ........................ 8-29
Brakes .......................................................................... 8-21
Brakes, front and rear .................................................... 5-3CCables, checking and lubricating ................................. 8-28
Carburetor, adjusting ...................................................8-19
Chassis fasteners ........................................................... 5-6
Cleaning ......................................................................... 9-1DDrive chain ..................................................................... 5-3
Drive chain, lubricating ................................................ 8-27
Drive chain slack .......................................................... 8-25
Drive select lever ............................................................ 4-6
Drive select lever and driving in reverse ........................ 6-3EEngine break-in .............................................................. 6-4
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-19
Engine oil .............................................................. 5-3, 8-11
Engine, starting a warm ................................................. 6-3Engine stop switch ......................................................... 4-2
FFront and rear brake shoes, checking ......................... 8-21
Front knuckle pivots, lubricating .................................. 8-30
Fuel ........................................................................ 4-8, 5-3
Fuel cock ...................................................................... 4-10
Fuel tank cap ................................................................. 4-8
Fuse, replacing ............................................................. 8-33HHandlebar switches ....................................................... 4-2IIdentification numbers ................................................. 11-1
Indicator lights ............................................................... 4-1
Instruments and switches .............................................. 5-6KKickstarter ...................................................................... 4-7LLabel locations ............................................................... 1-1MMain switch .................................................................... 4-1
Maintenance and lubrication chart ................................ 8-5
Maintenance chart, emission control system ................ 8-3
Model label .................................................................. 11-1NNeutral indicator light ..................................................... 4-1OOwner’s manual and tool kit .......................................... 8-2PParking ........................................................................... 6-5
UBD361E0.book Page 1 Monday, January 25, 2016 10:53 AM