2017 YAMAHA YFZ50 check engine

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 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
UBW460E0.book Page 13 Monday, May 23, 2016 11:12 AM

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 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)
UBW460E0.book Page 14 Monday, May 23, 2016 11:12 AM

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
UBW460E0.book Page 18 Monday, May 23, 2016 11:12 AM

8-20
8
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

8-21
8
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. EBU33950Adjusting the throttle lever free playThe throttle lever free play should be checked and,
if necessary, adjusted at the intervals specified in
the periodic maintenance and lubrication chart.
The throttle lever free play should measure 2.0–3.2
mm (0.08–0.13 in) as shown. Periodically check
the throttle lever free play and, if necessary, adjust
it as follows.TIPThe engine idling speed must be checked, and
adjusted if necessary, 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).
1. Throttle stop screwEngine idling speed:1600–1800 r/min
(a)
(b)
1
UBW460E0.book Page 21 Monday, May 23, 2016 11:12 AM

8-22
84. 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.
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.
1. Rubber cover
2. Throttle lever free play adjusting nut
3. Locknut
4. Throttle lever free play
1
2
3
1
4
(a)(b)
UBW460E0.book Page 22 Monday, May 23, 2016 11:12 AM

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.
UBW460E0.book Page 38 Monday, May 23, 2016 11:12 AM

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
UBW460E0.book Page 1 Monday, May 23, 2016 11:12 AM