check engine YAMAHA YFZ50 2017 User Guide

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EBU36870Periodic maintenance chart for the emission control systemTIPFor ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.
 For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance inter-
vals. However, keep in mind that if the ATV isn’t used for a long period of time, the month maintenance
intervals should still be followed.
 Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills. 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 80 160 160 320
1 *Fuel line • Check fuel hoses for cracks or other damage, and
replace if necessary. √√√
2Spark plug • Check condition and clean, regap, or replace if
necessary. √√√√√
3 *Va l v e s • Check valve clearance and adjust if necessary. √ √√√
4 *Carburetor • Check starter (choke) operation and correct if
necessary.
• Check engine idling speed and adjust if neces- sary. √ √√√
5 *Crankcase breath-
er system • Check breather hose for cracks or other damage,
and replace if necessary. √√√
UBW460E0.book Page 3 Tues
day, June 7, 2016 4:17 PM

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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 320UBW460E0.book Page 7 Tues day, June 7, 2016 4:17 PM

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EBU23081Removing and installing the panelThe panel shown needs to be removed to perform
some of the maintenance jobs described in this
chapter. Refer to this section each time the panel
needs to be removed and installed.EBU23102Panel A
To remove the panelRemove the bolts, and then take the panel off.To install the panel
Place the panel in the original position and install
the bolts.EBU23214Checking the spark plugThe spark plug is an important engine component,
which is easy to check. Since heat and deposits
will cause any spark plug to slowly erode, the
spark plug should be removed and checked in ac-
cordance with the periodic maintenance and lubri-
cation chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
1. Panel A
1
1. Panel A
2. Bolt
2
2
1
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8To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown, with the spark plug wrench included in the owner’s
tool kit. To check the spark plug
1. Check that the porcelain insulator around the center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).
TIPIf the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.
1. Spark plug cap
1
1. Spark plug wrench
1
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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.EBU36791Engine 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, 8.7 lb·ft)
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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, be sure to warm up the engine sufficiently,
and then wait at least ten minutes until the oil set-
tles 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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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 replace it if necessary.
7. Insert the dipstick into the oil filler hole, and then 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. Apply a thin coat of clean engine oil to a 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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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 replace it if necessary.
10. Install and tighten the engine oil filler cap.
11. 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.
12. 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: 0.90 L (0.95 US qt, 0.79 Imp.qt)
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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
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WARNING
EWB02341Do not start the engine when cleaning the
spark arrester, otherwise it could cause injury
to the eyes, burns, carbon monoxide poison-
ing, possibly leading to death, and start a fire.
Always let the exhaust system cool prior to
touching exhaust components. 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.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.
Tightening torque:
Tailpipe bolt:10 N·m (1.0 kgf·m, 7.2 lb·ft)
UBW460E0.book Page 20 Monday, May 23, 2016 11:12 AM