YAMAHA YFM250R 2011 Owners Manual

8-15
8 4. Loosen the wing bolt.
5. Remove the air filter element together with the
wing bolt and washer.6. Remove the wing bolt and washer from the air
filter element.
7. Remove the sponge material from the air filter
element frame.
1. Air filter case cover
2. Air filter case cover holder
12
1. Air filter element
2. Washer
3. Wing bolt
3 1
2
U1BT61E0.book Page 15 Tuesday, April 6, 2010 1:28 PM

8-16
88. Wash the sponge material gently but thor-
oughly in solvent. WARNING! Always use
parts cleaning solvent to clean the sponge
material. Never use low-flash-point sol-
vents or gasoline to clean the sponge ma-
terial because the engine could catch fire
or explode.
[EWB01941]
9. Squeeze the excess solvent out of the sponge
material and let it dry. NOTICE: Do not twist
the sponge material when squeezing it.
[ECB00441]
10. Check the sponge material and replace it if
damaged.
11. Apply Yamaha foam air filter oil or other qual-
ity foam air filter oil to the sponge material.TIPThe sponge material should be wet but not drip-
ping.12. Pull the sponge material over the air filter ele-
ment frame.
13. Apply all-purpose grease to the air filter ele-
ment seat.
1. Sponge material
2. Air filter element frame
1
2
U1BT61E0.book Page 16 Tuesday, April 6, 2010 1:28 PM

8-17
8 14. 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:
Be sure to install the washer with its
curved side facing outward as shown.
[ECB00453]
15. Insert the air filter element into the air filter
case, and then tighten the wing bolt. NOTICE:
Make sure that the air filter element is
properly seated in the air filter case. Never
operate the engine with the air filter ele-
ment removed. This will allow unfiltered air
to enter the engine, causing rapid engine
wear and possible engine damage. Addi-
tionally, operation without the air filter ele-
ment will affect carburetor jetting with
subsequent poor performance and possi-
ble engine overheating.
[ECB00461]
16. Install the air filter case cover by hooking the
holders onto the air filter case.
1. Air filter element seat
1
1. Washer
1
U1BT61E0.book Page 17 Tuesday, April 6, 2010 1:28 PM

8-18
817. Install the seat.
TIPThe 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.EBU28902Cleaning 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, and then remove the gasket.
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.
1. Bolt
2. Tailpipe
2
11
U1BT61E0.book Page 18 Tuesday, April 6, 2010 1:28 PM

8-19
8 4. Check the gasket for damage, and replace it if
necessary.
5. Make sure the gasket is properly positioned,
then insert the tailpipe into the muffler and
align the bolt holes.6. Install the bolts and tighten them to the speci-
fied torque.
WARNING
EWB02340Do not start the engine when cleaning the
spark arrester, otherwise it could cause injury
to the eyes, burns, carbon monoxide poison-
1. Tailpipe
2. Spark arrester
2 1
1. Gasket
2. Tailpipe
3. BoltTightening torque:
Tailpipe bolt:
11 Nm (1.1 m·kgf, 8.0 ft·lbf)
1 2
33
U1BT61E0.book Page 19 Tuesday, April 6, 2010 1:28 PM

8-20
8ing, possibly leading to death, and start a fire.
Always let the exhaust system cool prior to
touching exhaust components.
EBU23940Adjusting 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.NOTICEECB00480The 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.
EBU24000Adjusting 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.TIPA diagnostic tachometer is needed to make this
adjustment.1. Start the engine and warm it up.TIPThe 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).
U1BT61E0.book Page 20 Tuesday, April 6, 2010 1:28 PM

8-21
8
TIPIf the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment.
EBU24045Adjusting 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
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.TIPThe engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle ca-
ble free play.1. Slide the rubber cover back.
2. Loosen the locknut.
3. 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).
1. Throttle stop screwEngine idling speed:
1500–1600 r/min
1
(a)
(b)
U1BT61E0.book Page 21 Tuesday, April 6, 2010 1:28 PM

8-22
8
4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24060Valve 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.
EBU29601Brakes Replacement of brake components requires pro-
fessional knowledge. Brake service should be per-
formed by a Yamaha dealer.
WARNING
EWB02571Operating with improperly serviced or adjust-
ed brakes could lead to a loss in braking ability
and an accident.EBU24130Checking 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.EBUM0190Front 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.
1. Rubber cover
2. Throttle cable free play adjusting bolt
3. Locknut
4. Throttle cable free play
4 2 1
3
(a)
(b)
U1BT61E0.book Page 22 Tuesday, April 6, 2010 1:28 PM

8-23
8
TIPThe wheels need to be removed to check the
brake pads. (See page 8-42.)EBU28800Rear brake pads
Each brake pad is provided with two wear indicator
grooves, which allow you to check the brake pad
wear without having to disassemble the brake. To
check the brake pad wear, check the wear indica-
tor grooves. If a brake pad has worn to the point
that a wear indicator groove almost appears, have
a Yamaha dealer replace the brake pads as a set.
EBU29840Checking 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.
1. Wear indicator groove
1
1. Wear indicator groove
1
U1BT61E0.book Page 23 Tuesday, April 6, 2010 1:28 PM

8-24
8Front brake
Rear brakeObserve these precautions:

When checking the fluid level, make sure that
the top of the brake fluid reservoir is level.
Use only the recommended quality brake fluid,
otherwise the rubber seals may deteriorate,
causing leakage and poor braking performance.
Refill with the same type of brake fluid. Mixing
fluids may result in a harmful chemical reaction
and lead to poor braking performance.
Be careful that water does not enter the brake
fluid reservoir when refilling. Water will signifi-
cantly lower the boiling point of the fluid and may
result in vapor lock.
Brake fluid may deteriorate painted surfaces or
plastic parts. Always clean up spilled fluid imme-
diately.
As the brake pads wear, it is normal for the brake
fluid level to gradually go down. However, if the
brake fluid level goes down suddenly, have a
Yamaha dealer check the cause.
1. Minimum level mark
1. Minimum level mark
1
1
Recommended brake fluid:
DOT 4
U1BT61E0.book Page 24 Tuesday, April 6, 2010 1:28 PM