engine oil YAMAHA YFZ50 2018 Owners Manual

EBU17421
TABLE OF CONTENTS
LOCATION OF THE WARNING AND
SPECIFICATION LABELS .............................. 1-1
SAFETY INFORMATION ................................ 2-1
DESCRIPTION................................................ 3-1Left view ...................................................... 3-1
Right view.................................................... 3-1
Controls and instruments............................ 3-2
INSTRUMENT AND CONTROL
FUNCTIONS ................................................... 4-1 Main switch ................................................. 4-1
Handlebar switches .................................... 4-1
Engine stop switch with lanyard ................. 4-2
Throttle lever ............................................... 4-3
Speed limiter ............................................... 4-3
Front brake lever ......................................... 4-5
Rear brake lever .......................................... 4-6
Parking brake .............................................. 4-6
Kickstarter ................................................... 4-7
Fuel tank cap .............................................. 4-8
Fuel ............................................................. 4-8
Fuel cock................................................... 4-10 Starter (choke) ......................................... 4-11
Seat .......................................................... 4-12
Adjusting the rear shock absorber ........... 4-13
PRE-OPERATION CHECKS .......................... 5-1 Fuel ............................................................. 5-3
Engine oil .................................................... 5-3
Transmission oil .......................................... 5-3
Front and rear brakes ................................. 5-3
Throttle lever ............................................... 5-3
Drive chain .................................................. 5-3
Tires ............................................................ 5-3
Chassis fasteners ....................................... 5-6
Instruments and switches........................... 5-6
OPERATION .................................................. 6-1 Starting a cold engine................................. 6-1
Starting a warm engine............................... 6-3
Engine break-in........................................... 6-3
Parking........................................................ 6-3
Parking on a slope ...................................... 6-4
Accessories and loading ............................ 6-5UBW461E0.book Page 1 Tuesda y, January 31, 2017 5:13 PM

RIDING YOUR ATV ........................................ 7-1GETTING TO KNOW YOUR ATV ................ 7-2
RIDE WITH CARE AND GOOD JUDGMENT .............................................. 7-2
BE CAREFUL WHERE YOU RIDE ............... 7-9
TURNING YOUR ATV................................ 7-12
CLIMBING UPHILL ................................... 7-13
RIDING DOWNHILL .................................. 7-16
CROSSING A SLOPE................................ 7-17
CROSSING THROUGH SHALLOW WATER .................................................... 7-18
RIDING OVER ROUGH TERRAIN ............. 7-20
SLIDING AND SKIDDING .......................... 7-20
WHAT TO DO IF... ..................................... 7-21
WHAT TO DO... ......................................... 7-22
PERIODIC MAINTENANCE AND
ADJUSTMENT................................................ 8-1 Owner’s manual and tool kit ....................... 8-2
Periodic maintenance chart for the emission control system ........................... 8-3
General maintenance and lubrication chart .......................................................... 8-5
Removing and installing the panel .............. 8-9
Checking the spark plug ............................. 8-9
Engine oil................................................... 8-11
Transmission oil ........................................ 8-14 Cleaning the air filter element ................... 8-16
Cleaning the spark arrester ...................... 8-19
Adjusting the carburetor ........................... 8-20
Adjusting the engine idling speed ............ 8-20
Adjusting the throttle lever free play ......... 8-21
Valve clearance......................................... 8-22
Brakes....................................................... 8-22
Checking the front and rear brake
shoes ...................................................... 8-22
Adjusting the front brake lever free play... 8-23
Adjusting the rear brake lever free play .... 8-25
Drive chain slack....................................... 8-26
Cleaning and lubricating the drive chain ....................................................... 8-28
Checking and lubricating the cables ........ 8-29
Checking and lubricating the front and rear brake levers ..................................... 8-29
Checking the wheel hub bearings ............ 8-30
Lubricating the front arm pivots ............... 8-30
Lubricating the front knuckle pivots ......... 8-31
Lubricating the steering shaft ................... 8-31
Battery ...................................................... 8-32
Replacing the fuse .................................... 8-35
Removing a wheel .................................... 8-35
Installing a wheel ...................................... 8-36
Troubleshooting........................................ 8-37
Troubleshooting chart .............................. 8-38UBW461E0.book Page 2 Tuesda y, January 31, 2017 5:13 PM

2-5
2
4. Once immediate safety hazards are con-
firmed not to exist, you may remove your hel-
met to more closely inspect your vehicle.
Check for external signs of wear, broken
parts, fluid leaks, cracks in the frame, sus-
pension damage, wheel damage, and so on.
Fuel, oil, and coolant usually give off a notice-
able odor.
5. If your vehicle will not restart or if it is unsafe to ride, then turn off all vehicle systems (en-
gine stop switch, main switch, and fuel cock),
and then signal or go for help.
Aftermarket Parts, Accessories, and Modifica-
tions
While you may find aftermarket products similar in
design and quality to genuine Yamaha accesso-
ries, recognize that some aftermarket accessories
or modifications are not suitable because of po-
tential safety hazards to you or others. Installing
aftermarket products or having other modifica-
tions performed to your vehicle that change any of
the vehicle’s design or operation characteristics
can put you and others at greater risk of serious
injury or death. You are responsible for injuries re-
lated to changes in the vehicle. Keep the following
guidelines in mind, as well as those found in the Loading section (page 6-6) when mounting acces-
sories.

Never install accessories that would impair the
performance of your ATV. Carefully inspect the
accessory before using it to make sure that it
does not in any way reduce ground clearance,
limit suspension travel, steering travel or control
operation.
 Accessories fitted to the ATV can create insta-
bility due to improper weight distribution.
 Bulky or large accessories may seriously affect
the stability of the ATV.
 Certain accessories can displace the operator
from his or her normal riding position. This im-
proper position limits the freedom of movement
of the operator and may limit control ability,
therefore, such accessories are not recom-
mended.
 Use caution when adding electrical accesso-
ries. If electrical accessories exceed the capac-
ity of the ATV’s electrical system, an electric
failure could result, which could cause a dan-
gerous loss of lights or engine power. Also, the
battery tends to discharge more quickly if elec-
trical accessories are added.
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3-1
3
EBU17681
DESCRIPTION
EBU17691Left view
EBU17701Right view
1. Fuel tank cap
2. Fuel cock
3. Air filter
4. Engine stop switch with cord (lanyard)
5. Rear shock absorber spring preload adjuster
6. Kickstarter lever cap
7. Throttle stop screw
12
4
5
3
6
7
1. Spark arrester
2. Owner’s tool kit
3. Fuse
4. Battery
5. Spark plug
6. Engine oil filler cap
7. Transmission oil filler cap
12
3,4
5
67
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5-1
5
EBU19203
PRE-OPERATION CHECKS
EBU19226Inspect your vehicle each time you use it to make sure the vehicle is in safe operating condition. Always
follow the inspection and maintenance procedures and schedules described in the Owner’s Manual.
WARNING
EWB00482Failure to inspect or maintain the vehicle properly increases the possibility of an accident or equip-
ment damage. Do not operate the vehicle if you find any problem. If a problem cannot be corrected
by the procedures provided in this manual, have the vehicle inspected by a Yamaha dealer. Before using this vehicle, check the following points:
ITEMROUTINE PAGE
Fuel • Check fuel level in fuel tank,
and add recommended fuel if neces-
sary.
• Check fuel line for leakage. Correct if necessary. 4-8, 5-3
Engine oil • Check oil level in engine, and add recommended oil to specified
level if necessary.
• Check ATV for oil leakage. Correct if necessary. 5-3, 8-11
Transmission oil • Check ATV for oil leakage. Correct if necessary. 5-3, 8-14
Front brake • Check operation, and correct if necessary.
• Lubricate cable if necessary.
• Check lever free play, and adjust if necessary. 5-3, 8-22, 8-23
Rear brake • Check operation, and correct if necessary.
• Lubricate cable if necessary.
• Check lever free play, and adjust if necessary. 5-3, 8-22, 8-25
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5-3
5
EBU19542FuelMake sure that there is sufficient fuel in the tank.
(See page 4-8.)EBU19561Engine oilMake sure that the engine oil is at the specified
level. Add oil as necessary. (See page 8-11.)EBU34490Transmission oilMake sure that the transmission oil is at the spec-
ified level. Add oil as necessary. (See page 8-14.)EBU19653Front and rear brakesBrake levers
Check for correct free play in the brake levers. If
the free play is incorrect, adjust it. (See pages
8-23 and 8-25.)
 Check operation of the levers. They should
move smoothly and there should be a firm feel-
ing when the brake is applied. If not, have the
ATV checked by a Yamaha dealer. Brake operation
Test the brakes at slow speed after starting out to
make sure they are working properly. If the brakes
do not provide proper braking performance,
check the brake shoes for wear. (See page 8-22.)
EBU19762Throttle leverCheck the operation of the throttle lever. It must
open smoothly and spring back to the idle position
when released. Have a Yamaha dealer correct if
necessary.EBU19771Drive chainCheck the condition of the drive chain and check
the drive chain slack. Lubricate and adjust the
drive chain as necessary. (See page 8-26.)EBU19797TiresCheck tire pressure regularly to make sure it is at
the recommended specifications. Also check for
wear and damage.
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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 320UBW461E0.book Page 7 Tuesda y, January 31, 2017 5:13 PM

8-11
8
2. Check the spark plug for electrode erosion
and excessive carbon or other deposits, and
replace it if necessary.
3. Measure the spark plug gap with a wire thick- ness gauge and, if necessary, adjust the gap
to specification. To install the spark plug
1. Clean the surface of the spark plug gasket and its mating surface, and then wipe off any
grime from the spark plug threads.
2. Install the spark plug with the spark plug wrench, and then tighten it to the specified
torque.
TIPIf a torque wrench is not available when installing
the spark plug, a good estimate of the correct
torque is 1/4–1/2 turn past finger tight. However,
the spark plug should be tightened to the speci-
fied torque as soon as possible. 3. Install the spark plug cap.EBU37000Engine oilThe engine oil level should be checked before
each ride. In addition, the oil must be changed at
the intervals specified in the periodic maintenance
and lubrication chart.
Specified spark plug:
NGK/CR6HSA
1. Spark plug gapSpark plug gap:0.6–0.7 mm (0.024–0.028 in)
Tightening torque:Spark plug:12 N·m (1.2 kgf·m, 8.9 lb·ft)
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8-12
8To check the engine oil level
1. Place the ATV on a level surface.
2. Check the engine oil level on a cold engine.
TIPIf the engine was started before checking the oil
level, warm up the engine and then wait at least
ten minutes until the oil settles for an accurate
reading. 3. Remove the engine oil filler cap, and then wipe the engine oil dipstick off with a clean
rag. 4. Insert the dipstick into the filler hole, screw it
in, and then remove it again to check the oil
level.
TIPThe engine oil should be between the minimum
and maximum level marks. 5. If the engine oil is at or below the minimumlevel mark, add sufficient oil of the recom-
mended type to raise it to the correct level.
1. Engine oil filler cap
1
1. Engine oil filler cap
2. O-ring
3. Engine oil dipstick
4. Maximum level mark
5. Minimum level mark
14523
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8-13
8
NOTICE:
Be sure the engine oil is at the
correct level, otherwise engine damage
may result.
[ECB00852]
6. Check the O-ring for damage, and then insert the dipstick and tighten the engine oil filler
cap.
To change the engine oil 1. Place the ATV on a level surface.
2. Start the engine, warm it up for several minu- tes, and then turn it off.
3. Place an oil pan under the engine to collect the used oil.
4. Remove the engine oil filler cap, and then re- move the engine oil drain bolt to drain the oil
from the crankcase. NOTICE: When remov-
ing the engine oil drain bolt, the compres-
sion spring, oil strainer and O-ring will fall
out. Take care not to lose these parts.
[ECB00312]
5. Clean the oil strainer with solvent.
6. Discard the old engine oil drain bolt O-ring, and then apply a thin coat of clean engine oil
to the new O-ring.
7. Install the oil strainer, the compression spring, the new O-ring and the engine oil
drain bolt. Tighten the engine oil drain bolt to
the specified torque. NOTICE: Before in-
stalling the engine oil drain bolt, be sure to
install the O-ring, compression spring and
oil strainer.
[ECB00322]
1. Oil strainer
2. Compression spring
3. O-ring
4. Engine oil drain bolt
1234
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