2008 YAMAHA YFM250R check engine

8-16
1
2
3
4
5
6
78
9
10
11

7. Wash the sponge material gently but thor-
oughly in solvent.
WARNING

EWB01940
Always use parts cleaning solvent to clean the
sponge material. Never use low-flash-point
solvents or gasoline to clean the sponge mate-
rial because the engine could catch fire or ex-
plode.
8. Squeeze the excess solvent out of the sponge
material and let it dry.CAUTION:

ECB00440
Do not twist the sponge material when squeez-
ing it.
9. Check the sponge material and replace it if
damaged.
10. Apply a quality foam air filter oil to the sponge
material.
NOTE:

The sponge material should be wet but not drip-
ping.
11. Pull the sponge material over the air filter ele-
ment frame.
1. Sponge material
2. Air filter element frame
1
2

8-17
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2
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78
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12. Install the washer onto the air filter element
frame, and then insert the wing bolt into the
hole in the air filter element frame.
CAUTION:

ECB00451
Be sure to install the washer with the bent edge
facing outward as shown.
13. Insert the air filter element into the air filter
case, and then tighten the wing bolt.
14. Install the air filter case cover by hooking the
holders onto the air filter case.
15. Install the seat.
NOTE:

The 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 dusty ar-
eas. Each time the air filter element maintenance
is performed, check the air inlet of the air filter case
for obstructions. Check the air filter case rubber
joint to the carburetor fittings and the rubber joint
manifold fittings for an air-tight seal. Tighten all fit-
tings securely to avoid the possibility of unfiltered
air entering the engine.
CAUTION:

ECB00460

Make sure that the air filter element is prop-
erly seated in the air filter case.

Never operate the engine with the air filter el-
ement removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addition-
ally, operation without the air filter element
will affect carburetor jetting with subsequent
poor performance and possible engine over-
heating.
1. Washer
1

8-19
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2
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4
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6
78
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5. Install the bolts and tighten them to the speci-
fied torque.
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
touching exhaust components.
EBU23940
Adjusting the carburetor
The carburetor should be checked and, if neces-
sary, adjusted at the intervals specified in the peri-
odic maintenance and lubrication chart. The
carburetor is an important part of the engine and
requires very sophisticated adjustment. Therefore,
most carburetor adjustments should be left to a
Yamaha dealer, who has the necessary profes-
sional knowledge and experience. The adjustment
described in the following section, however, may
be performed by the owner as part of routine main-
tenance.
CAUTION:

ECB00480
The 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.
1. Gasket
2. Tailpipe
3. Bolt
Tightening torque:
Tailpipe bolt:
11 Nm (1.1 m·kgf, 8.0 ft·lbf)
1 2
33

8-20
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78
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EBU24000
Adjusting the engine idling speed
The engine idling speed must be checked and, if
necessary, adjusted as follows at the intervals
specified in the periodic maintenance and lubrica-
tion chart.
NOTE:

A diagnostic tachometer is needed to make this
adjustment.
1. Start the engine and warm it up.
NOTE:

The engine is warm when it quickly responds to the
throttle.
2. Attach the tachometer to the spark plug lead.
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).
NOTE:

If the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment.
EBU24043
Adjusting the throttle cable free play
The throttle cable free play should be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
1. Throttle stop screw
Engine idling speed:
1500–1600 r/min
1
(a)
(b)

8-21
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chart.
The throttle cable free play should measure 2.0–
4.0 mm (0.08–0.16 in) at the throttle lever. Period-
ically check the throttle cable free play and, if nec-
essary, adjust it as follows.
NOTE:

The engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle ca-
ble free play.
1. Loosen the locknut.
2. To increase the throttle cable free play, turn
the adjusting bolt in direction (a). To decrease
the throttle cable free play, turn the adjusting
bolt in direction (b).
3. Tighten the locknut.
EBU24060
Valve clearance
The 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.
1. Locknut
2. Throttle cable free play adjusting bolt
3. Throttle lever free play
3 2
1
(a)(b)

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the drive chain with steam cleaners, high-pres-
sure washers or inappropriate solvents.
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a
special O-ring chain lubricant.
CAUTION:

ECB00580
Do not use engine oil or any other lubricants
for the drive chain, as they may contain sub-
stances that could damage the O-rings.
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.
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.
EBU24921
Checking and lubricating the brake and
clutch levers
The operation of the brake and clutch levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary.
Recommended lubricant:
Engine oil
Recommended lubricants:
Brake lever:
Silicone grease
Clutch lever:
Lithium-soap-based grease (all-purpose
grease)

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EBU25751
Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
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.
Have a Yamaha dealer
check the ATV.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Open the throttle halfway and operate
the electric starter.

INDEX
A
Accessories and loading ................................................ 6-6
Air filter element, cleaning ............................................ 8-14
B
Battery .......................................................................... 8-36
Brake and clutch levers, checking and lubricating ....... 8-33
Brake and shift pedals, checking and lubricating ......... 8-34
Brake fluid, changing.................................................... 8-25
Brake fluid level, checking............................................ 8-23
Brake lever ..................................................................... 4-5
Brake lever free play, checking the front ...................... 8-26
Brake light switches ..................................................... 8-29
Brake pads, checking the front and rear ...................... 8-22
Brake pedal .................................................................... 4-5
Brake pedal position, checking .................................... 8-26
Brakes, front and rear .................................................... 5-3
C
Cables, checking and lubricating ................................. 8-33
Carburetor, adjusting.................................................... 8-19
Chassis fasteners........................................................... 5-7
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-4
Clutch lever free play, adjusting ................................... 8-29
D
Drive chain ..................................................................... 5-4
Drive chain, lubricating ................................................. 8-32Drive chain slack .......................................................... 8-30
E
Engine break-in .............................................................. 6-5
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-20
Engine oil ....................................................................... 5-3
Engine oil and oil filter element .................................... 8-10
Engine, starting a warm ................................................. 6-3
Engine stop switch ......................................................... 4-2
F
Fuel ........................................................................ 4-7
,
5-3
Fuel cock ........................................................................ 4-8
Fuel tank cap.................................................................. 4-7
Fuse, replacing............................................................. 8-37
H
Handlebar switches ........................................................ 4-2
Headlight beam, adjusting............................................ 8-41
Headlight bulb, replacing.............................................. 8-39
I
Identification numbers .................................................. 11-1
Indicator light .................................................................. 4-1
Instruments, lights and switches .................................... 5-7
K
Key identification number ............................................. 11-1
L
Label locations ............................................................... 2-1