2008 YAMAHA YFM350R check engine

8-17
8
CAUTION:ECB00440Do not twist the sponge material when squeez-ing it.
7. Check the sponge material and replace it if
damaged.
8. Apply a quality foam air filter oil to the sponge
material.NOTE:The sponge material should be wet but not drip-ping.
9. Pull the sponge material over the air filter ele-
ment frame.10. Apply all-purpose grease to the air filter ele-
ment seat.
11. Insert the air filter element into the air filter
case, and then install the air filter case cover
by hooking the holders onto the air filter case.
12. 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 unfilteredair 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
U5YT64E0.book Page 17 Monday, April 9, 2007 1:03 PM

8-19
8 7. Start the engine and rev it up approximately
twenty times while momentarily creating ex-
haust system back pressure by blocking the
end of the muffler with a shop towel.
8. Stop the engine and allow the exhaust pipe to
cool.
9. Install the purging bolt and tighten it to the
specified torque.
WARNING
EWB02380Never run the engine in an enclosed area when
purging the spark arrester, otherwise it could
cause injury to the eyes, burns, carbon monox-
ide poisoning, possibly leading to death, and
start a fire.
Always let the exhaust system cool prior to
touching exhaust components.
Always wear eye protection, and make sure
no one is behind the ATV.
Make sure there are no combustible materi-als in the area.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
1. Purging boltTightening torque:
Purging bolt:
27 Nm (2.7 m·kgf, 19 ft·lbf)
U5YT64E0.book Page 19 Monday, April 9, 2007 1:03 PM

8-20
8described in the following section, however, may
be performed by the owner as part of routine main-
tenance.
CAUTION:ECB00480The 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 ordamage 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.NOTE:A diagnostic tachometer is needed to make thisadjustment.
1. Start the engine and warm it up.NOTE:The engine is warm when it quickly responds to thethrottle.
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 theadjustment.1. Throttle stop screwEngine idling speed:
1450–1550 r/min
U5YT64E0.book Page 20 Monday, April 9, 2007 1:03 PM

8-21
8
EBU24043Adjusting 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.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.
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.1. Locknut
2. Throttle cable free play adjusting bolt
3. Throttle cable free play
U5YT64E0.book Page 21 Monday, April 9, 2007 1:03 PM

8-32
8
CAUTION:ECB00560The drive chain must be lubricated after wash-ing the ATV or riding in the rain.
1. Clean the drive chain with kerosene and a
small soft brush.CAUTION:ECB00570To prevent damaging the O-rings, do not clean
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:ECB00580Do not use engine oil or any other lubricants
for the drive chain, as they may contain sub-stances that could damage the O-rings.EBU24900Checking 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
EWB02130Inspect 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 anaccident or injury.
1. O-ring
Recommended lubricant:
Engine oil
U5YT64E0.book Page 32 Monday, April 9, 2007 1:03 PM

8-44
8
EBU25751Troubleshooting 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.
U5YT64E0.book Page 44 Monday, April 9, 2007 1:03 PM

9-3
9 c. Install the spark plug cap onto the spark
plug, and then place the spark plug on the
cylinder head so that the electrodes are
grounded. (This will limit sparking during
the next step.)
d. Turn the engine over several times with the
starter. (This will coat the cylinder wall with
oil.)
e. Remove the spark plug cap from the spark
plug, and then install the spark plug and
the spark plug cap.
6. Lubricate all control cables and the pivoting
points of all levers and pedals.
7. Check and, if necessary, correct the tire air
pressure, and then block up the ATV so that
all of its wheels are off the ground. Alternative-
ly, turn the wheels a little every month in order
to prevent the tires from becoming degraded
in one spot.
8. Cover the muffler outlet with a plastic bag to
prevent moisture from entering it.
9. Remove the battery and fully charge it. Store
it in a cool, dry place and charge it once a
month. Do not store the battery in an exces-
sively cold or warm place [less than 0 °C (30°F) or more than 30 °C (90 °F)]. For more in-
formation on storing the battery, see page
8-37.
NOTE:Make any necessary repairs before storing theATV.
U5YT64E0.book Page 3 Monday, April 9, 2007 1:03 PM

INDEX
AAccessories and loading ................................................ 6-8
Air filter element, cleaning ............................................ 8-14BBattery .......................................................................... 8-37
Brake and clutch levers, checking and lubricating ....... 8-33
Brake and shift pedals, checking and lubricating ......... 8-33
Brake fluid, changing .................................................... 8-24
Brake fluid level, checking ............................................ 8-23
Brake lever ..................................................................... 4-5
Brake lever free play, checking the front ...................... 8-24
Brake light switches ..................................................... 8-27
Brake pads, checking the front and rear ...................... 8-22
Brake pedal .................................................................... 4-5
Brake pedal position, checking .................................... 8-25
Brakes, front and rear .................................................... 5-3CCables, checking and lubricating ................................. 8-32
Carburetor, adjusting .................................................... 8-19
Chassis fasteners ........................................................... 5-7
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-5
Clutch lever free play, adjusting ................................... 8-28DDrive chain ..................................................................... 5-4
Drive chain, lubricating ................................................. 8-31
Drive chain slack .......................................................... 8-29
Drive select lever ............................................................ 4-7Drive select lever and driving in reverse ........................ 6-3
EEngine break-in .............................................................. 6-6
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-20
Engine oil ....................................................................... 5-3
Engine oil and oil filter element .................................... 8-11
Engine, starting a warm ................................................. 6-3
Engine stop switch ......................................................... 4-2FFuel ......................................................................... 4-8, 5-3
Fuel cock ........................................................................ 4-9
Fuel tank cap .................................................................. 4-8
Fuse, replacing ............................................................. 8-38HHandlebar switches ........................................................ 4-2
Headlight beam, adjusting ............................................ 8-41
Headlight bulb, replacing .............................................. 8-39IIdentification numbers .................................................. 11-1
Indicator lights ................................................................ 4-2
Instruments, lights and switches .................................... 5-7KKey identification number ............................................. 11-1LLabel locations ............................................................... 2-1
Light switch .................................................................... 4-3
U5YT64E0.book Page 1 Monday, April 9, 2007 1:03 PM