engine YAMAHA YFM90 2018 Workshop Manual

8-34
8
EBU25246Replacing the fuseIf an electrical problem is suspected, check the
fuse and replace it if necessary as follows.NOTICEECB00641To prevent accidental short-circuiting, turn off
the main switch when checking or replacing a
fuse. 1. Turn off all electrical systems. (See page 4-1.)
2. Remove the seat. (See page 4-12.)3. Remove the blown fuse, and then install a
new fuse of the specified amperage.
WARNING! Always use a fuse of the spec- ified rating, and never use a substitute ob-
ject in place of the proper fuse. An
improper fuse or a substitute object can
cause damage to the electrical system,
which could lead to a fire.
[EWB02173]
4. Turn on the main switch and start the engine.
5. If the fuse immediately blows again, have a Yamaha dealer check the vehicle.EBU34030Removing a wheel1. Place the ATV on a level surface.
2. Loosen the wheel bolts.
1. Fuse
2. Spare fuse
2 1
Specified fuse:
7.5 A
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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.
UBD362E0.book Page 37 Tuesday, January 31, 2017 5:10 PM

9-1
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.
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)UBD362E0.book Page 2 Tuesday, January 31, 2017 5:10 PM

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10
EBU25962
SPECIFICATIONS
Dimensions:Overall length:1485 mm (58.5 in)
Overall width: 1020 mm (40.2 in)
Overall height:
955 mm (37.6 in)
Seat height: 750 mm (29.5 in)
Wheelbase: 1030 mm (40.6 in)
Ground clearance:
100 mm (3.9 in)
Minimum turning radius: 3000 mm (118 in)Weight:Curb weight:
126.5 kg (279 lb)Noise and vibration level:Noise level (77/311/EEC):73.0 dB(A) (EUR, FRA, GBR)
Uncertainty of measurement:
3.0 dB(A) (EUR, FRA, GBR)
Vibration on seat (EN1032, ISO5008): 0.6 m/s² (EUR, FRA, GBR)
Uncertainty of measurement: 0.3 m/s² (EUR, FRA, GBR) Vibration on handle (EN1032, ISO5008):
6.3 m/s² (EUR, FRA, GBR)
Uncertainty of measurement: 1.3 m/s² (EUR, FRA, GBR)
Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement: Single cylinder
Displacement: 90 cm³
Bore × stroke:
47.0 × 51.8 mm (1.85 × 2.04 in)
Compression ratio: 9.2 : 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:0.80 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:
6.6 L (1.74 US gal, 1.45 Imp.gal)
Fuel reserve amount: 0.9 L (0.24 US gal, 0.20 Imp.gal)Carburetor:Type × quantity:
H66D 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: 35/14 (2.500)
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
INDEX
AAccessories and loading ................................................ 6-6
Air filter element, cleaning ............................................ 8-15BBattery .......................................................................... 8-31
Brake lever free play, adjusting the front ..................... 8-22
Brake lever free play (rear), adjusting ........................... 8-24
Brake lever, front ............................................................ 4-4
Brake lever, rear ............................................................. 4-5
Brake levers, checking and lubricating ........................ 8-29
Brakes .......................................................................... 8-21
Brakes, front and rear .................................................... 5-3CCables, checking and lubricating ................................. 8-28
Carburetor, adjusting ...................................................8-19
Chassis fasteners ........................................................... 5-6
Cleaning ......................................................................... 9-1DDrive chain ..................................................................... 5-3
Drive chain, lubricating ................................................ 8-27
Drive chain slack .......................................................... 8-25
Drive select lever ............................................................ 4-6
Drive select lever and driving in reverse ........................ 6-3EEngine break-in .............................................................. 6-4
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-19
Engine oil .............................................................. 5-3, 8-11
Engine, starting a warm ................................................. 6-3Engine stop switch ......................................................... 4-2
FFront and rear brake shoes, checking ......................... 8-21
Front knuckle pivots, lubricating .................................. 8-30
Fuel ........................................................................ 4-8, 5-3
Fuel cock ...................................................................... 4-10
Fuel tank cap ................................................................. 4-8
Fuse, replacing ............................................................. 8-34HHandlebar switches ....................................................... 4-2IIdentification numbers ................................................. 11-1
Indicator lights ............................................................... 4-1
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 .................................................................. 11-1NNeutral indicator light ..................................................... 4-1OOwner’s manual and tool kit .......................................... 8-2PParking ........................................................................... 6-5
UBD362E0.book Page 1 Tuesday, January 31, 2017 5:10 PM