engine YAMAHA YFZ50 2017 Workshop Manual

8-38
8
EBU25754Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.There is no fuel.
Check the battery.
Supply fuel.
The engine does not start.
Check the battery.
The engine does not start.
Check the ignition.
Operate the electric starter.4. Compression
There is compression.
There is no compression.
The engine does not start. Have a Yamaha dealer check the ATV.Have a Yamaha dealer check the ATV.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug. Have a Yamaha dealer check the ATV.
The engine does not start.
Check the compression.
Operate the electric starter.2. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and have a Yamaha dealer charge
the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.
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9
EBU25861
CLEANING AND STORAGE
EBU25903CleaningFrequent, thorough cleaning of your ATV will not
only enhance its appearance but will improve its
general performance and extend the useful life of
many components.1. Before cleaning the ATV: a. Block off the end of the exhaust pipe toprevent water entry. A plastic bag and
strong rubber band may be used.
b. Make sure the spark plug and all filler caps are properly installed.
2. If the engine case is excessively greasy, apply degreaser with a paint brush. Do not apply
degreaser to the chain, sprockets or wheel
axles.
3. Rinse the dirt and degreaser off with a garden hose. Use only enough pressure to do the
job. WARNING! Wet brakes may have re-
duced stopping ability, increasing the
chance of an accident. Test the brakes af-
ter washing. Apply the brakes several
times at slow speeds to let friction dry out
the linings.
[EWB02312]
NOTICE: Excessive wa- ter pressure may cause water seepage
and deterioration of wheel bearings,
brakes, transmission seals and electrical
devices. Many expensive repair bills have
resulted from improper high-pressure de-
tergent applications such as those avail-
able in coin-operated car washers.
[ECB00712]
4. Once most of the dirt has been hosed off,
wash all surfaces with warm water and mild,
detergent-type soap. An old toothbrush or
bottle brush is handy for hard-to-reach pla-
ces.
5. Rinse the ATV off immediately with clean wa- ter and dry all surfaces with a chamois, clean
towel or soft absorbing cloth.
6. Dry the chain and lubricate it to prevent it from rusting.
7. Clean the seat with a vinyl upholstery cleaner to keep the cover pliable and glossy.
8. Automotive type wax may be applied to all painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
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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.
EBU30361StorageShort-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. Follow all the instructions in the “Cleaning” section of this chapter.
2. Turn the fuel cock lever to “OFF”.
3. Drain the carburetor float chamber by loosen- ing the drain bolt; this will prevent fuel depos-
its from building up. Pour the drained fuel into
the fuel tank. 4. Fill up the fuel tank and add fuel stabilizer (if
available) to prevent the fuel from deteriorat-
ing.
5. Perform the following steps to protect the cyl- inder, piston rings, etc. from 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.)
e. Remove the spark plug cap from the spark plug, and then install the spark plug and
the spark plug cap.
6. Lubricate all control cables and the pivoting points of all levers.
Specified amount:
7.5 ml of stabilizer to each liter of fuel (or 1
oz of stabilizer to each gallon of fuel)UBW460E0.book Page 2 Monday, May 23, 2016 11:12 AM

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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
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:0.90 L (0.95 US qt, 0.79 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:
VM12Spark 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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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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