engine oil YAMAHA YFZ50 2018 User Guide

8-14
88. Refill with the specified amount of the recom-
mended engine oil.
TIPBe sure to wipe off spilled oil on any parts after the
engine and exhaust system have cooled down. NOTICEECB00331Do not use oils with a diesel specification of
“CD” or oils of a higher quality than speci-
fied. In addition, do not use oils labeled “EN-
ERGY CONSERVING II” or higher.
 Make sure that no foreign material enters the
crankcase.
9. Check the engine oil filler cap O-ring for dam-
age, and then install and tighten the engine oil
filler cap.
10. Start the engine, and then let it idle for several minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
11. Turn the engine off, wait at least ten minutes, and then check the oil level and correct it if
necessary.EBU34472Transmission oilThe transmission case must be checked for oil
leakage before each ride. If any leakage is found,
have a Yamaha dealer check and repair the ATV.
In addition, the transmission oil must be changed
at the intervals specified in the periodic mainte-
nance and lubrication chart.
To change the transmission oil1. Place the ATV on a level surface.
2. Place an oil pan under the transmission case to collect the used oil.
3. Remove the transmission oil filler cap and its O-ring from the transmission case.
Tightening torque:
Engine oil drain bolt:25 N·m (2.5 kgf·m, 18 lb·ft)
Recommended oil: See page 10-1.
Oil quantity: 0.80 L (0.85 US qt, 0.70 Imp.qt)
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8-18
86. 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- ment 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
UBW461E0.book Page 18 Tuesday, January 31, 2017 5:13 PM

8-28
84. 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 8-25.)
EBU36480Cleaning and lubricating 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. Remove all dirt and mud from the drive chainwith a brush or cloth.TIPFor a thorough cleaning, have a Yamaha dealer re-
move the drive chain and soak it in solvent. 2. Spray Yamaha chain lubricant or other suit-able chain lubricant on the entire chain, mak-
ing sure that all side plates and rollers have
been sufficiently oiled.
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)
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9-2
9abrasives which may mar the paint or protec-
tive finish. When finished cleaning, start the
engine and let it idle for several minutes.
EBU30362StorageShort-term
Always store your ATV in a cool, dry place and, if
necessary, protect it against dust with a porous
cover.
NOTICE: Storing the ATV in a poorly ven-
tilated room or covering it with a tarp while it is
still wet, will allow water and humidity to seep
in and cause rust. To prevent corrosion, avoid
damp cellars, stables (because of the presence
of ammonia) and areas where strong chemi-
cals are stored.
[ECB00722]
Long-term
Before storing your ATV for several months: 1. Make any necessary repairs and perform all outstanding maintenance.
2. Follow all the instructions in the Cleaning sec- tion of this chapter. 3. Fill up the fuel tank and add fuel stabilizer (Fu-
el Med Rx if available), and then run the en-
gine for 5 minutes to distribute the treated
fuel.
4. Turn the fuel cock lever off, and then drain the carburetor float chamber by loosening the
drain bolt. Pour the drained fuel into the fuel
tank.
5. Perform the following steps to protect the en- gine from internal corrosion.a. Remove the spark plug cap and spark plug.
b. Pour a teaspoonful of engine oil into the spark plug bore.
c. Install the spark plug cap onto the spark plug, and then place the spark plug on the
cylinder head so that the electrodes are
grounded. (This will limit sparking during
the next step.)
d. Turn the engine over several times with the starter. (This will coat the cylinder wall
with oil.)
Specified amount:
7.5 ml per liter of fuel (1 oz per gallon)UBW461E0.book Page 2 Tuesda y, January 31, 2017 5:13 PM

10-1
10
EBU25962
SPECIFICATIONS
Dimensions:Overall length:1250 mm (49.2 in)
Overall width: 820 mm (32.3 in)
Overall height:
770 mm (30.3 in)
Seat height: 585 mm (23.0 in)
Wheelbase: 830 mm (32.7 in)
Ground clearance:
88 mm (3.5 in)
Minimum turning radius: 2300 mm (91 in)Weight:Curb weight:
100.0 kg (220 lb)Noise and vibration level:Noise level (77/311/EEC):74.0 dB(A) (EUR, FRA, GBR)
Uncertainty of measurement:
2.0 dB(A) (EUR, FRA, GBR)
Vibration on seat (EN1032, ISO5008): Will not exceed 0.5 m/s² (EUR, FRA, GBR)
Uncertainty of measurement: 0.1 m/s² (EUR, FRA, GBR) Vibration on handle (EN1032, ISO5008):
4.7 m/s² (EUR, FRA, GBR)
Uncertainty of measurement: 0.4 m/s² (EUR, FRA, GBR)
Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement: Single cylinder
Displacement: 49 cm³
Bore × stroke:
39.0 × 41.4 mm (1.54 × 1.63 in)
Compression ratio: 8.5 : 1
Starting system: Electric starter and kickstarter
Lubrication system:
Wet sumpEngine oil:Recommended brand:YAMALUBE
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10-2
10
Type:SAE 5W-30, 10W-30, 10W-40, 15W-40, 20W-40 or 20W-
50
Recommended engine oil grade: API service SG type or higher, JASO standard MA
Engine oil quantity: Periodic oil change:0.80 L (0.85 US qt, 0.70 Imp.qt)Transmission oil:Type:
SAE 80W-90
Quantity: 0.35 L (0.37 US qt, 0.31 Imp.qt)Air filter:Air filter element:
Wet element
Fuel:Recommended fuel:Regular unleaded gasoline only
Fuel tank capacity:
5.6 L (1.48 US gal, 1.23 Imp.gal)
Fuel reserve amount: 0.7 L (0.18 US gal, 0.15 Imp.gal)Carburetor:Type × quantity:
VM12 X 1Spark plug (s):Manufacturer/model: NGK/CR6HSA
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)Clutch:Clutch type:Dry, centrifugal automaticTransmission:Secondary reduction system:Chain drive
Secondary reduction ratio: 38/13 (2.920)
Transmission type:
V-belt automatic
Operation: Centrifugal automatic typeChassis:Frame type:
Steel tube frame
0 10 30 50 70 90 110 130 ˚F
–20 –10 0 10 20 30 40 50 ˚CSAE 5W-30
SAE 10W-30
SAE 10W-40
SAE 15W-40
SAE 20W-40SAE 20W-50
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12-1
12
INDEX
AAccessories and loading ................................................ 6-5
Air filter element, cleaning ............................................ 8-16BBattery .......................................................................... 8-32
Brake lever free play, adjusting the front ..................... 8-23
Brake lever free play (rear), adjusting ........................... 8-25
Brake lever, front ............................................................ 4-5
Brake lever, rear ............................................................. 4-6
Brake levers, checking and lubricating ........................ 8-29
Brakes .......................................................................... 8-22
Brakes, front and rear .................................................... 5-3CCables, checking and lubricating ................................. 8-29
Carburetor, adjusting ...................................................8-20
Chassis fasteners ........................................................... 5-6
Cleaning ......................................................................... 9-1DDrive chain ..................................................................... 5-3
Drive chain, cleaning and lubricating ........................... 8-28
Drive chain slack .......................................................... 8-26EEngine break-in .............................................................. 6-3
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-20
Engine oil .............................................................. 5-3, 8-11
Engine, starting a warm ................................................. 6-3
Engine stop switch ......................................................... 4-1
Engine stop switch with lanyard .................................... 4-2
FFront and rear brake shoes, checking ......................... 8-22
Front arm pivots, lubricating ........................................ 8-30
Front knuckle pivots, lubricating .................................. 8-31
Fuel ........................................................................ 4-8, 5-3
Fuel cock ...................................................................... 4-10
Fuel tank cap ................................................................. 4-8
Fuse, replacing ............................................................. 8-35HHandlebar switches ....................................................... 4-1IIdentification numbers ................................................. 11-1
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 .................................................................. 11-1OOwner’s manual and tool kit .......................................... 8-2PPanel, removing and installing ....................................... 8-9
Parking ........................................................................... 6-3
Parking brake ................................................................. 4-6
Parking on a slope ......................................................... 6-4
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