check engine YAMAHA YFM50R 2008 Owners Manual

EBU17420
TABLE OF CONTENTS
SAFETY INFORMATION .............................. 1-1
LOCATION OF THE WARNING AND
SPECIFICATION LABELS ............................ 2-1
DESCRIPTION .............................................. 3-1
Left view ..................................................... 3-1
Right view................................................... 3-1
Controls and instruments ........................... 3-2
INSTRUMENT AND CONTROL
FUNCTIONS .................................................. 4-1
Main switch ............................................... 4-1
Indicator light ............................................. 4-1
Handlebar switches ................................... 4-2
Engine stop switch with lanyard ................ 4-2
Throttle lever ............................................. 4-4
Speed limiter ............................................. 4-5
Front brake lever ....................................... 4-6
Rear brake lever ........................................ 4-6
Parking brake ............................................ 4-6
Drive select lever ....................................... 4-7
Fuel tank cap ............................................. 4-7
Fuel ........................................................... 4-8
Fuel cock ................................................... 4-9Choke ...................................................... 4-10
Seat ......................................................... 4-11
PRE-OPERATION CHECKS ..........................5-1
Pre-operation check list ............................. 5-1
Fuel ............................................................ 5-3
Engine oil ................................................... 5-3
Final gear oil .............................................. 5-3
Front and rear brakes ................................ 5-3
Throttle lever .............................................. 5-4
Tires ........................................................... 5-4
Measuring the tire pressure ....................... 5-5
Tire wear limit ............................................ 5-6
Chassis fasteners ...................................... 5-6
Instruments, lights and switches ................ 5-6
Battery ....................................................... 5-6
OPERATION...................................................6-1
Starting a cold engine ................................ 6-1
Starting a warm engine .............................. 6-3
Shifting ....................................................... 6-3
Engine break-in .......................................... 6-5
Parking ....................................................... 6-5
Parking on a slope ..................................... 6-6
Accessories and loading ............................ 6-7

RIDING YOUR ATV ...................................... 7-1
GETTING TO KNOW YOUR ATV.............. 7-2
RIDE WITH CARE AND GOOD
JUDGEMENT ........................................... 7-2
BE CAREFUL WHERE YOU RIDE ............ 7-9
TURNING YOUR ATV ............................. 7-12
CLIMBING UPHILL .................................. 7-14
RIDING DOWNHILL................................. 7-16
CROSSING A SLOPE.............................. 7-17
CROSSING THROUGH SHALLOW
WATER .................................................. 7-18
RIDING OVER ROUGH TERRAIN .......... 7-20
SLIDING AND SKIDDING ........................ 7-20
WHAT TO DO IF... ................................... 7-21
WHAT TO DO... ....................................... 7-21
PERIODIC MAINTENANCE AND MINOR
REPAIR .......................................................... 8-1
Owner’s manual and tool kit ...................... 8-1
Periodic maintenance chart for the
emission control system .......................... 8-3
General maintenance and lubrication
chart ........................................................ 8-5
Checking the spark plug ............................ 8-8
Engine oil .................................................. 8-9
Final gear oil ............................................ 8-12
Cleaning the air filter element ................. 8-13
Cleaning the spark arrester ..................... 8-17
Adjusting the carburetor .......................... 8-18Adjusting the engine idling speed ............ 8-18
Checking the throttle cable free play ....... 8-19
Valve clearance ....................................... 8-19
Checking the front and rear brake
shoes ..................................................... 8-20
Adjusting the front brake lever free play .. 8-21
Adjusting the rear brake lever free play ... 8-23
Checking and lubricating the cables ........ 8-24
Checking and lubricating the front and
rear brake levers .................................... 8-25
Checking the wheel hub bearings ............ 8-25
Lubricating the front knuckle pivots ......... 8-25
Lubricating the steering shaft ................... 8-26
Battery ..................................................... 8-26
Replacing the fuse ................................... 8-28
Removing a wheel ................................... 8-29
Installing a wheel ..................................... 8-30
Troubleshooting ....................................... 8-31
Troubleshooting chart .............................. 8-32
CLEANING AND STORAGE ..........................9-1
Cleaning ..................................................... 9-1
Storage ...................................................... 9-2
SPECIFICATIONS .......................................10-1
CONSUMER INFORMATION.......................11-1
Identification numbers .............................. 11-1

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Avoid crossing the side of a steep hill if possible.

Always use proper procedures if you stall or roll
backwards when climbing a hill. If you stall or roll
backwards, follow the special procedure for
braking described in this manual. Dismount on
the uphill side or to a side if pointed straight up-
hill. Turn the ATV around and remount, following
the procedure described in this manual.

Always check for obstacles before operating in a
new area.

Never attempt to operate over large obstacles,
such as large rocks or fallen trees. Always follow
proper procedures when operating over obsta-
cles as described in this manual.

Always be careful when skidding or sliding.
Learn to safely control skidding or sliding by
practicing at low speeds and on level, smooth
terrain. On extremely slippery surfaces, such as
ice, go slowly and be very cautious in order to re-
duce the chance of skidding or sliding out of con-
trol.

Never operate an ATV in fast flowing water or in
water deeper than that recommended in this
manual. Remember that wet brakes may have
reduced stopping ability. Test your brakes after
leaving water. If necessary, apply them severaltimes to let friction dry out the linings.

Always use the size and type of tires specified in
this manual.

Always maintain proper tire pressure as de-
scribed in this manual.

Never modify an ATV through improper installa-
tion or use of accessories.

Never exceed the stated load capacity for an
ATV. Cargo should be properly distributed and
securely attached. Reduce speed and follow in-
structions in this manual for carrying cargo or
pulling a trailer. Allow greater distance for brak-
ing.
TEACHING YOUR CHILD TO OPERATE THE
ATV
WARNING

EWB00080
Never let your child ride an ATV without close
adult supervision (a child under 6 should not
ride this ATV even with adult supervision).
Promptly correct your child if he or she begins
to ride beyond his or her abilities and, if neces-
sary, intervene by pulling the cord (lanyard) to
stop the engine.
If the child rides beyond his or her abilities, or
rides in terrain that is too difficult, he or she

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For further explanation of this switch and the lan-
yard, see “TEACHING YOUR CHILD TO OPER-
ATE THE ATV” in the “SAFETY INFORMATION”
section.
NOTE:


The engine cannot be started with the clip re-
moved.

When your child has developed sufficient skill to
no longer need you to follow with the lanyard,
the lanyard can be stowed under the seat of the
ATV. However, you must still closely supervise
your child at all times during ATV operation.
EBU18280
Throttle lever
Once the engine is running, movement of the throt-
tle lever will increase the engine speed.
Regulate the speed of the ATV by varying the
throttle position. Because the throttle is spring-
loaded, the ATV will decelerate, and the engine will
return to an idle any time the hand is removed from
the throttle lever.
Before starting the engine, check the throttle to be
sure it is operating smoothly. Make sure it returns
to the idle position as soon as the lever is released.
1. Lanyard
1

1. Throttle lever
1

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WARNING

EWB00250
Malfunction of the throttle could make it diffi-
cult to speed up or slow down when you need
to. This could cause an accident. Check the op-
eration of the throttle lever before you start the
engine. If the throttle does not work smoothly,
check for the cause. Correct the problem be-
fore riding the ATV or consult a Yamaha dealer.
EBU18361
Speed limiter
Your ATV was delivered with an adjustable speed
limiter. Yamaha recommends that all beginning
riders start off with the speed limiter adjusting
screw fully turned in to limit the amount of speed
available while they learn.
The speed limiter keeps the throttle from fully
opening, even when the throttle lever is pushed to
the maximum. The adjusting screw may be gradu-
ally turned out as the beginner becomes more fa-
miliar with operating the ATV.
1. Loosen the locknut.
2. To increase the maximum engine power avail-
able and the maximum speed of the ATV, turn
the adjusting screw in direction (a). To de-crease the maximum engine power available
and the maximum speed of the ATV, turn the
adjusting screw in direction (b).
3. Tighten the locknut.WARNING
EWB00230
Improper adjustment of the speed limiter and
throttle could cause throttle cable damage or
improper throttle operation. The child could
lose control, have an accident or be injured. Do
not turn the adjusting screw out more than 12
1. Locknut
2. Adjusting screw
3. No more than 12 mm (0.47 in)
1
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(b)
(a)

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EBU19200
PRE-OPERATION CHECKS
EBU19222
Pre-operation check list
Before operating this ATV, be sure to check the items listed in the following table.
WARNING

EWB00480
Always inspect your ATV each time you use it to make sure it is in safe operating condition.
Always follow the inspection and maintenance procedures and schedules described in the Owner’s
Manual. Failure to inspect increases the possibility of an accident or equipment damage.
NOTE:

The maintenance of some items in the table has to be performed by a Yamaha dealer. Refer to the periodic
maintenance charts on page 8-3 to determine which service should be performed by a Yamaha dealer.
ITEM ROUTINE PAGE
Fuel


Check fuel level in fuel tank, and add recommended fuel if neces-
sary.

Check fuel line for leakage. Correct if necessary.4-8, 5-3
Engine oil

Check oil level in engine, and add recommended oil to specified
level if necessary.

Check ATV for oil leakage. Correct if necessary.5-3, 8-9
Final gear oil

Check ATV for oil leakage. Correct if necessary. 5-3, 8-12
Front brake

Check operation, and correct if necessary.

Lubricate cable if necessary.

Check lever free play, and adjust if necessary.5-3, 8-20, 8-21

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EBU19540
Fuel
Make sure that there is sufficient fuel in the tank.
(See page 4-8.)
WARNING

EWB00520

Do not overfill the fuel tank. Fuel expands
when it heats up. If the fuel tank is overfilled,
fuel could spill out due to heat from the en-
gine or the sun.

Be careful not to spill fuel, especially on the
engine or exhaust pipe which can cause a
fire and severe injury. Wipe up any spilled
fuel immediately.

Do not refuel right after the engine has been
running and is still very hot.

Be sure the fuel tank cap is closed securely.
EBU19560
Engine oil
Make sure that the engine oil is at the specified lev-
el. Add oil as necessary. (See page 8-9.)
EBU19590
Final gear oil
Make sure that the final gear oil is at the specified
level. Add oil as necessary. (See page 8-12.)
EBU19650
Front and rear brakes
Brake levers

Check for correct free play in the brake levers. If
the free play is incorrect, adjust it. (See pages
8-21 and 8-23.)

Check operation of the levers. They should
move smoothly and there should be a firm feel-
ing when the brake is applied. If not, have the
ATV checked by a Yamaha dealer.
Brake operation
Test the brakes at slow speed after starting out to
make sure they are working properly. If the brakes
do not provide proper braking performance, check
the brakes for wear. (See page 8-20.)
WARNING

EWB00570
Always check the brakes at the start of every
ride. Do not ride the ATV if you find any prob-
lem with the brakes or you could lose braking
ability, which could lead to an accident. If a
problem cannot be corrected by the adjust-
ment procedures provided in this manual, have
the ATV checked by a Yamaha dealer.

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EBU19880
OPERATION
EBU19900
Read the Owner’s Manual carefully before riding
the ATV.
WARNING

EWB00630
Read the Owner’s Manual carefully to become
familiar with all controls in order to help pre-
vent any loss of control, which could cause an
accident or injury. If there is a control or func-
tion you do not understand, ask your Yamaha
dealer.
EBU20241
Starting a cold engine
WARNING

EWB00640
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do
not work smoothly, you could be unable to
control the ATV, which could lead to an acci-
dent or collision.
CAUTION:

ECB00150
See the “Engine break-in” section on page 6-5
prior to operating the engine for the first time.
1. Set the parking brake.
2. Turn the fuel cock to “ON”.
3. Turn the main switch to “ON” and the engine
stop switch to “RUN”.
4. Shift the transmission into neutral. The neutral
indicator light should come on. If the indicator
light does not come on, have a Yamaha deal-
er check the electrical circuit.
NOTE:

This model is equipped with an ignition circuit cut-
off system. The engine can be started under the
following conditions.

The transmission is in neutral.

The rear brake lever is applied with the drive se-
lect lever in the drive position. However, it is rec-
ommended to shift into neutral before starting
the engine.

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EBU20682
Engine break-in
NOTE:


For ATVs equipped with an odometer or an hour
meter, follow the figures given in km (mi) or the
figures given in hours.

For ATVs not equipped with an odometer or
hour meter, follow the figures given in hours.
There is never a more important period in the life of
your engine than the first 320 km (200 mi) or 20
hours of riding. For this reason, you should read
the following material carefully.
Since the engine is brand new, do not put an ex-
cessive load on it for the first 320 km (200 mi) or 20
hours. The various parts in the engine wear and
polish themselves to the correct operating clear-
ances. During this period, prolonged full-throttle
operation or any condition that might result in en-
gine overheating must be avoided.
0–160 km (0–100 mi) or 0–10 hours
Avoid prolonged operation above 1/2 throttle. Vary
the speed of the ATV regularly. Do not operate it at
one set throttle position.
160–320 km (100–200 mi) or 10–20 hours
Avoid prolonged operation above 3/4 throttle. Rev
the engine freely, but do not use full throttle at any
time.
320 km (200 mi) or 20 hours and beyond
The ATV can now be operated normally.CAUTION:

ECB00220
If any engine trouble should occur during the
engine break-in period, immediately have a
Yamaha dealer check the ATV.
EBU26770
Parking
When parking the ATV, stop the engine, shift the
drive select lever into the drive position, apply the
parking brake, and then turn the fuel cock to “OFF”.

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EBU21742
Periodic maintenance chart for the emission control system
NOTE:


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 be followed.

Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills.
NO. ITEMCHECK OR MAINTENANCE
JOBINITIAL EVERY
Whichev-
er comes
firstmonth 1 3 6 6 12
km
(mi)320
(200)1300
(800)2500
(1600)2500
(1600)5000
(3200)
hours 20 80 160 160 3201
*
Fuel line


Check fuel hoses for cracks or other damage, and
replace if necessary.
√√√
2 Spark plug

Check condition and clean, regap, or replace if
necessary.
√√√√√
3
*
Valves


Check valve clearance and adjust if necessary.
√ √√√
4
*
Carburetor


Check choke operation and correct if necessary.

Check engine idling speed and adjust if neces-
sary.
√√√√
5
*
Crankcase breather
system


Check breather hose for cracks or other damage,
and replace if necessary.
√√√