2009 YAMAHA YFM250R Owners Manual

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13. Install the washer onto the air filter element
frame, and then insert the wing bolt into the
hole in the air filter element frame.
NOTICE

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

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.
NOTICE

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

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EBU28900
Cleaning the spark arrester
Be sure the exhaust pipe and muffler are cool be-
fore cleaning the spark arrester.
1. Remove the bolts.
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 inside
of the tailpipe housing.4. Make sure the gasket is properly positioned,
then insert the tailpipe into the muffler and
align the bolt holes.
1. Bolt
2. Tailpipe
2
11

1. Tailpipe
2. Spark arrester
2 1

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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 injuryto 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.
NOTICE

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

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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.
TIP

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

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).
TIP

If the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment.
EBU24044
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)

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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.
TIP

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 throttle cable free play adjusting bolt in di-
rection (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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EBU24130
Checking the front and rear brake pads
The front and rear brake pads must be checked for
wear at the intervals specified in the periodic main-
tenance and lubrication chart.
EBUM0190
Front brake pads
Each brake pad is provided with a wear indicator
groove, which allows you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor groove. If a brake pad has worn to the point that
the wear indicator groove has almost disappeared,
have a Yamaha dealer replace the brake pads as
a set.
TIP

The wheels need to be removed to check the
brake pads. (See page 8-42.)
EBU24190
Rear brake pads
Each brake pad is provided with a wear indicator,
which allows you to check the brake pad wear
without having to disassemble the brake. To check
the brake pad wear, check the position of the wear
indicator while applying the brake. If a brake pad
has worn to the point that the wear indicator almost
touches the brake disc, have a Yamaha dealer re-
1. Wear indicator groove
1

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place the brake pads as a set.
EBU28930
Checking the brake fluid level
Insufficient brake fluid may allow air to enter the
brake system, possibly causing it to become inef-
fective.
Before riding, check that the brake fluid is above
the minimum level mark and replenish if neces-
sary. A low brake fluid level may indicate worn
brake pads and/or brake system leakage. If the
brake fluid level is low, be sure to check the brake
pads for wear and the brake system for leakage.
Front brake
1. Wear indicator
1

1. Minimum level mark1

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Rear brake

If the rear brake fluid level is low, replenish as fol-
lows.
1. Remove the brake fluid reservoir cap cover by
removing the bolt.2. Remove the brake fluid reservoir cap.
1. Minimum level mark
1

1. Bolt
2. Brake fluid reservoir cap cover
1
2