2008 YAMAHA YFM50R light

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hill. Avoid sharp angles which could allow the ATV
to tip or roll over. Carefully choose your path and
ride no faster than you will be able to react to ob-
stacles which may appear.
WARNING

EWB01620
Always follow proper procedures for going
down hills as described in this Owner’s Manu-
al.
Note: a special technique is required when
braking as you go down a hill.

Always check the terrain carefully before
you start down any hill.

Shift your weight backward.

Never go down a hill at high speed.

Avoid going down a hill at an angle that
would cause the ATV to lean sharply to one
side. Go straight down the hill where possi-
ble.CROSSING A SLOPE
Traversing a sloping surface on your ATV requires
you to properly position your weight to maintain
proper balance. Be sure that you have learned the
basic riding skills on flat ground before attempting
to cross a sloping surface. Avoid slopes with slip-
pery surfaces or rough terrain that may upset your
balance.
As you travel across a slope, lean your body in the
uphill direction. It may be necessary to correct the
steering when riding on loose surfaces by pointing
the front wheels slightly uphill. When riding onOK

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EBU23211
Checking the spark plug
The 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 accor-
dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown, with thespark 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).NOTE:

If 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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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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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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Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
56 mm (2.2 in)
Electrical system:
Ignition system:
CDI
Charging system:
AC magneto
Battery:
Model:
12N7D-3B
Voltage, capacity:
12 V, 7.0 Ah
Bulb voltage, wattage x quantity:
Neutral indicator light:
12 V, 1.7 W
×
1
Fuses:
Main fuse:
5.0 A

INDEX
A
Accessories and loading ................................................ 6-7
Air filter element, cleaning ............................................ 8-13
B
Battery .................................................................. 5-6
,
8-26
Brake lever free play, adjusting the front...................... 8-21
Brake lever free play (rear), adjusting .......................... 8-23
Brake lever, front ............................................................ 4-6
Brake lever, rear............................................................. 4-6
Brake levers, checking and lubricating......................... 8-25
Brakes, front and rear .................................................... 5-3
Brake shoes, checking the front and rear .................... 8-20
C
Cables, checking and lubricating ................................. 8-24
Carburetor, adjusting.................................................... 8-18
Chassis fasteners........................................................... 5-6
Choke ........................................................................... 4-10
Cleaning ......................................................................... 9-1
D
Drive select lever............................................................ 4-7
E
Engine break-in .............................................................. 6-5
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-18
Engine oil ............................................................... 5-3
,
8-9
Engine, starting a warm ................................................. 6-3Engine stop switch ......................................................... 4-2
Engine stop switch with lanyard ..................................... 4-2
F
Final gear oil......................................................... 5-3
,
8-12
Front knuckle pivots, lubricating ................................... 8-25
Fuel ........................................................................ 4-8
,
5-3
Fuel cock ........................................................................ 4-9
Fuel tank cap.................................................................. 4-7
Fuse, replacing............................................................. 8-28
H
Handlebar switches ........................................................ 4-2
I
Identification numbers .................................................. 11-1
Indicator light .................................................................. 4-1
Instruments, lights and switches .................................... 5-6
K
Key identification number ............................................. 11-1
L
Label locations ............................................................... 2-1
M
Main switch .................................................................... 4-1
Maintenance and lubrication chart ................................. 8-5
Maintenance chart, emission control system ................. 8-3
Model label ................................................................... 11-2
N
Neutral indicator light ..................................................... 4-1