2008 YAMAHA YFM50R warning

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poor performance and possible engine over-
heating.
EBU27630
Cleaning the spark arrester
Be sure the exhaust pipe and muffler are cool be-
fore cleaning the spark arrester.
1. Remove the screws.
2. Remove the tailpipe by pulling it out of the
muffler.
3. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from the
spark arrester portion of the tailpipe and insideof the tailpipe housing.
4. Insert the tailpipe into the muffler and align the
screw holes.
5. Install the screws and tighten them.WARNING
EWB02340
Do 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
1. Screw
1

1. Tailpipe
2. Spark arrester
3. Screw
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3

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4. Tighten the lower locknut.
5. While applying the front brake, turn out the up-
per adjusting bolt until the upper and lower ca-
ble lengths are equal. The cable joint will
become vertical.6. Tighten the upper locknut.
WARNING

EWB02080
Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident.
After servicing:

Make sure the brakes operate smoothly and
that the free play is correct.

Make sure the brakes do not drag.
Replacement of brake components requires
professional knowledge. These procedures
1. Upper locknut
2. Upper adjusting bolt
3. Lower locknut
4. Lower adjusting bolt
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3(a)(b)(a)
(b)

1. Cable joint
1

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adjusting nut on the brake cable at the rear
wheel hub in direction (a), and to decrease it,
turn the nut in direction (b).
7. Tighten the locknut at the brake lever.
NOTE:

If the specified free play cannot be obtained as de-
scribed above or if the rear brake does not operate
correctly, have a Yamaha dealer check the internal
rear brake mechanism.
WARNING
EWB02080
Operating with improperly serviced or adjust-
ed brakes could cause loss of braking ability,
which could lead to an accident.
After servicing:

Make sure the brakes operate smoothly and
that the free play is correct.

Make sure the brakes do not drag.
Replacement of brake components requires
professional knowledge. These procedures
should be performed by a Yamaha dealer.
EBU24900
Checking and lubricating the cables
The operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
1. Brake lever free play adjusting nut
1
(a)(b)

Recommended lubricant:
Engine oil

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WARNING

EWB02130
Inspect cables frequently and replace if dam-
aged. Corrosion can result when the cable
sheaths become damaged, and cables can
also become frayed or kinked, which could re-
strict the operation of controls and lead to an
accident or injury.
EBU28701
Checking and lubricating the front and
rear brake levers
The operation of the front and rear brake levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
EBU24962
Checking the wheel hub bearings
The front and rear wheel hub bearings must be
checked at the intervals specified in the periodic
maintenance and lubrication chart. If there is play
in a wheel hub or if a wheel does not turn smoothly,have a Yamaha dealer check the wheel hub bear-
ings.
EBU28821
Lubricating the front knuckle pivots
The front knuckle pivots must be lubricated at the
intervals specified in the periodic maintenance and
lubrication chart.
Lubricate the front knuckle pivots using a grease
gun.
Recommended lubricant:
Lithium-soap-based grease (all-purpose
grease)
Recommended lubricant:
Lithium-soap-based grease (all-purpose
grease)

1. Grease nipple
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EBU25101
Lubricating the steering shaft
The steering shaft must be lubricated at the inter-
vals specified in the periodic maintenance and lu-
brication chart.
EBU25121
Battery
A poorly maintained battery will corrode and dis-
charge quickly. The electrolyte level, battery lead
connections and breather hose routing should be
checked before each ride and at the intervals
specified in the periodic maintenance and lubrica-
tion chart.
To check the electrolyte level
1. Place the ATV on a level surface.
2. Check the electrolyte level in the battery.
NOTE:

The electrolyte should be between the minimum
and maximum level marks.
3. If the electrolyte is at or below the minimumlevel mark, add distilled water to raise it to the
maximum level mark.
CAUTION:

ECB00590
Use only distilled water, as tap water contains
minerals that are harmful to the battery.
WARNING

EWB02160
Battery electrolyte is poisonous and danger-
ous, as it contains sulfuric acid, which can
cause severe burns. Avoid contact with skin,
Recommended lubricant:
Lithium-soap-based grease (all-purpose
grease)
1. Maximum level mark
2. Minimum level mark
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CAUTION:

ECB00640
To prevent accidental short-circuiting, turn off
the main switch when checking or replacing a
fuse.
2. Remove the blown fuse, and then install a
new fuse of the specified amperage.
WARNING

EWB02171
Always use a fuse of the specified rating, and
never use a substitute object in place of the
proper fuse. An improper fuse or a substitute
object can cause damage to the electrical sys-
tem, which could lead to a fire.
3. Turn the key to “ON” and turn on the electrical
circuits to check if the devices operate.
4. If the fuse immediately blows again, have a
Yamaha dealer check the electrical system.
EBU25650
Removing a wheel
1. Loosen the wheel nuts.
Front
Specified fuse:
5.0 A
1. Wheel nut
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Rear

2. Lower the ATV to the ground.
3. Tighten the wheel nuts to the specified
torques.
EBU25720
Troubleshooting
Although Yamaha ATVs receive a thorough in-
spection before shipment from the factory, trouble
may occur during operation. Any problem in the fu-
el, compression, or ignition systems, for example,
can cause poor starting and loss of power.
The following troubleshooting chart represents a
quick and easy procedure for checking these vital
systems yourself. However, should your ATV re-
quire any repair, take it to a Yamaha dealer, whose
skilled technicians have the necessary tools, expe-
rience, and know-how to service the ATV properly.
Use only genuine Yamaha replacement parts. Im-
itation parts may look like Yamaha parts, but they
are often inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWB02280
Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.
1. Arrow mark
Tightening torques:
Front wheel nut:
28 Nm (2.8 m·kgf, 20 ft·lbf)
Rear wheel nut:
28 Nm (2.8 m·kgf, 20 ft·lbf)
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EBU25860
CLEANING AND STORAGE
EBU25880
Cleaning
Frequent, 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 to
prevent 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 de-
greaser to the wheel axles.
3. Rinse the dirt and degreaser off with a garden
hose. Use only enough pressure to do the job.
CAUTION:

ECB00710
Excessive water pressure may cause water
seepage and deterioration of wheel bearings,
brakes, transmission seals and electrical de-
vices. Many expensive repair bills have result-
ed from improper high-pressure detergentapplications such as those available in coin-
operated car washers.
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 bot-
tle brush is handy for hard-to-reach places.
5. Rinse the ATV off immediately with clean wa-
ter and dry all surfaces with a chamois, clean
towel or soft absorbing cloth.
6. Clean the seat with a vinyl upholstery cleaner
to keep the cover pliable and glossy.
7. Automotive type wax may be applied to all
painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
abrasives which may mar the paint or protec-
tive finish. When finished cleaning, start the
engine and let it idle for several minutes.WARNING
EWB02310
Wet brakes may have reduced stopping ability,
increasing the chance of an accident. Test the
brakes after washing. Apply the brakes several
times at slow speeds to let friction dry out the