2020 YAMAHA YFZ50 brake

8-7
8
15*Steering system • Check operation and repair or replace if dam-
aged.
• Check toe-in and adjust if necessary. √√√√√
16 Engine oil • Change.
• Check ATV for oil leakage, and correct if neces-
sary. √ √√√
17 Engine oil strainer • Clean. √√√
18 Transmission oil • Change.
• Check ATV for oil leakage, and correct if neces-
sary. √√
19 *Moving parts and
cables
• Lubricate.
√√√√
20 *Throttle lever • Check operation.
• Check throttle lever free play, and adjust if neces-
sary.
• Lubricate cable and lever housing. √√√√√
21 *Brake switch • Check operation and correct if necessary. √√√√√
22 *Switches • Check operation and correct if necessary. √√√√√
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev-
er comes first month136612
km (mi) 240
(150) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320UBW463E0.book Page 7 Monday, January 28, 2019 10:22 AM

8-22
8
EBU33951Adjusting the throttle lever free playPeriodically check the throttle lever free play and
adjust if necessary.TIPThe engine idling speed must be checked and ad-
justed before adjusting the throttle lever free play.
1. Slide the rubber covers apart.
2. Loosen the locknut.
3. To increase the throttle lever free play, turnthe throttle lever free play adjusting nut in di-
rection (a). To decrease the throttle lever free
play, turn the adjusting nut in direction (b).
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.
1. Rubber cover
2. Throttle lever free play adjusting nut
3. Locknut
4. Throttle lever free playThrottle lever free play:2.0–3.2 mm (0.08–0.13 in)
1
2
3
1
4
(a)(b)
UBW463E0.book Page 22 Monday, January 28, 2019 10:22 AM

8-23
8
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.Rear 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.
1. Upper adjusting bolt
2. Lower adjusting bolt
3. No more than 12 mm (0.47 in)
3
21
UBW463E0.book Page 23 Monday, January 28, 2019 10:22 AM

8-24
8
EBU24334Adjusting the front brake lever free
playPeriodically check the front brake lever free play
and adjust if necessary.1. Loosen the upper locknut and fully turn in the upper adjusting bolt.
2. Loosen the lower locknut.
3. Turn the lower adjusting bolt in direction (a) to increase the lever free play, and in direction
(b) to decrease it.
1. Rear brake lever free play adjusting nut
2. Bolt
3. No more than 18 mm (0.71 in)
1
2 3
1. Front brake lever free playFront brake lever free play:
9.3–13.3 mm (0.37–0.52 in)
1
UBW463E0.book Page 24 Monday, January 28, 2019 10:22 AM

8-25
84. Tighten the lower locknut.
5. While applying the front brake, turn out the
upper adjusting bolt until the upper and lower
cable lengths are equal. The cable joint will
become vertical. 6. Tighten the upper locknut.
TIPAfter adjusting the brake lever free play, check the
front brake shoes for wear.
1. Upper locknut
2. Upper adjusting bolt
3. Lower locknut
4. Lower adjusting bolt
1
2
4
3 (a)
(b)
1. Cable joint1
aa´ a=a´
UBW463E0.book Page 25 Monday, January 28, 2019 10:22 AM

8-26
8
EBU33784Adjusting the rear brake lever free playPeriodically check the rear brake lever free play
and adjust if necessary.
Turn the adjusting nut in direction (a) to increase
the brake lever free play, and in direction (b) to de-
crease it.
TIPAfter adjusting the brake lever free play, check the
rear brake shoes for wear. EBU34014Drive chain slackThe drive chain slack should be checked before
each ride and adjusted if necessary.TIPWhen checking and adjusting the drive chain
slack, there should be no weight on the ATV and
all tires must be touching the ground.
1. Rear brake lever free playRear brake lever free play:7.6–12.9 mm (0.30–0.51 in)1
1. Rear brake lever free play adjusting nut
1
(a)
(b)
UBW463E0.book Page 26 Monday, January 28, 2019 10:22 AM

8-27
8To check the drive chain slack
1. Place the ATV on a level surface.
2. Move the ATV back and forth to locate the tightest portion of the drive chain, and then
measure the drive chain slack as shown.
3. If the drive chain slack is incorrect, adjust it as follows.
To adjust the drive chain slack 1. Loosen the bolts and nuts. 2. Loosen the rear brake lever free play adjust-
ing nut.
Drive chain slack:
6.0–12.0 mm (0.24–0.47 in)
1. Drive chain slack
1
1. Bolt
1. Nut
1
1
UBW463E0.book Page 27 Monday, January 28, 2019 10:22 AM

8-28
8
3. Loosen the locknut. 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 8-26.)
1. Rear brake lever free play adjusting nut
1. Drive chain slack adjusting nut
2. Locknut
1
1
2(a)(b)
Tightening torques:Locknut:22 N·m (2.2 kgf·m, 16 lb·ft)
Bolt: 45 N·m (4.5 kgf·m, 33 lb·ft)
Nut: 54 N·m (5.4 kgf·m, 40 lb·ft)
UBW463E0.book Page 28 Monday, January 28, 2019 10:22 AM