YAMAHA YFZ50 2020 Owners Manual

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5. Install the transmission oil drain bolt and its
new gasket, and then tighten the bolt to the
specified torque.
6. Refill with the specified amount of the recom- mended oil. NOTICE: Make sure that no
foreign material enters the transmission
case.
[ECB03380]
7. Check the oil filler cap O-ring for damage, and replace it if necessary.
8. Install and tighten the oil filler cap.
9. Check the transmission case for oil leakage. If oil is leaking, check for the cause.EBU34110Cleaning the air filter elementThe air filter element should be serviced at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean or, if necessary, replace
the air filter element more frequently if you are rid-
ing in unusually wet or dusty areas.TIPThere is a check hose at the bottom of the air filter
case. If dust or water collects in this hose, empty
the hose and clean the air filter element and air fil-
ter case.
1. Transmission oil drain bolt
2. GasketTightening torque:Transmission oil drain bolt:30 N·m (3.0 kgf·m, 22 lb·ft)
12
Recommended oil: See page 10-1.
Oil quantity: 0.35 L (0.37 US qt, 0.31 Imp.qt)
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81. Park the ATV on a level surface.
2. Remove the seat. (See page 4-13.)
3. Remove the air filter case cover by unhooking
the air filter case cover holders. 4. Remove the air filter element, and clean it with
solvent. WARNING! Always use parts
cleaning solvent to clean the air filter ele-
ment. Never use low-flash-point solvents
or gasoline to clean the air filter element
because the engine could catch fire or ex-
plode.
[EWB03540]
1. Air filter case check hose
1
1. Air filter case cover
2. Air filter case cover holder
1
2
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5. Squeeze the excess solvent out of the air filter
element and let it dry. NOTICE: Do not twist
the air filter element when squeezing it.
[ECB02310]
6. Check the air filter element and replace it if damaged.
7. Apply Yamaha foam air filter oil or other qual- ity foam air filter oil to the element.TIPThe air filter element should be wet but not drip-
ping. 8. Insert the air filter element into the air filtercase.
9. Install the air filter case cover by hooking the holders onto the air filter case. NOTICE:
Make sure that the air filter element is
properly seated in the air filter case. Never
operate the engine with the air filter ele-
1. Air filter element
1
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8ment removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addi-
tionally, operation without the air filter ele-
ment will affect carburetor jetting with
subsequent poor performance and possi-
ble engine overheating.
[ECB00462]
10. Install the seat.TIPThe air filter element should be cleaned every 20–
40 hours. It should be cleaned and lubricated
more often if the ATV is operated in extremely dusty areas. When servicing the air filter element,
be sure to check the air inlet of the air filter case
for obstructions.
EBU28905Cleaning the spark arresterBe sure the exhaust pipe and muffler are cool be-
fore cleaning the spark arrester.1. Tailpipe bolt
2. Tailpipe
3. Spark arrester
4. Gasket
1
2
3
4
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WARNING
EWB02342Always let the exhaust system cool prior to
touching exhaust components.
Do not start the engine with the spark arrester
removed. Sparks or exhaust particulate can
cause eye injury, burns, or start a fire. 1. Remove the tailpipe bolts.
2. Remove the tailpipe by pulling it out of themuffler, and then remove the gasket.
3. Tap the tailpipe lightly, and then use a wire brush to remove any carbon deposits from
the spark arrester portion of the tailpipe and
inside of the tailpipe housing.
4. Check the gasket for damage. Replace if nec- essary.
5. Install the gasket onto the tailpipe, then insert the tailpipe into the muffler and align the bolt
holes.
6. Install the bolts and tighten to the specified torque.
EBU23941Adjusting the carburetorThe carburetor should be checked and, if neces-
sary, adjusted at the intervals specified in the pe-
riodic maintenance and lubrication chart. The
carburetor is an important part of the engine and
requires very sophisticated adjustment. There-
fore, most carburetor adjustments should be left
to a Yamaha dealer, who has the necessary pro-
fessional knowledge and experience. The adjust-
ment described in the following section, however,
may be performed by the owner as part of routine
maintenance.NOTICEECB00481The carburetor has been set and extensively
tested at the Yamaha factory. Changing these
settings without sufficient technical knowl-
edge may result in poor performance of or
damage to the engine. EBU24001Adjusting the engine idling speedThe engine idling speed must be checked and, if
necessary, adjusted as follows at the intervals
specified in the periodic maintenance and lubrica-
tion chart.
Tightening torque:
Tailpipe bolt:10 N·m (1.0 kgf·m, 7.4 lb·ft)
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TIPA diagnostic tachometer is needed to make this
adjustment. 1. Start the engine and warm it up.TIPThe engine is warm when it quickly responds to
the throttle. 2. Attach the tachometer to the spark plug lead.
3. Check the engine idling speed and, if neces-sary, adjust it to specification by turning the
throttle stop screw at the carburetor. To in-
crease the engine idling speed, turn the throt-
tle stop screw in direction (a), and to decrease
it, turn the screw in direction (b).
TIPIf the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment. 1. Throttle stop screwEngine idling speed:1600–1800 r/min
(a)
(b)
1
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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)
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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
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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
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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´
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