2004 YAMAHA YFM350R engine

8-41 1. Throttle stop screw
1. Vis de butée de papillon
1. Tornillo de tope del acelerador
EBU13020
Idle speed adjustmentNOTE:_ A diagnostic tachometer must be used for this pro-
cedure. _1. Start the engine and warm it up for a few min-
utes at approximately 1,000 to 2,000 r/min.
Occasionally rev the engine to 4,000 to
5,000 r/min. The engine is warm when it
quickly responds to the throttle.
2. Connect the tachometer to the spark plug
lead, and then set the idle to the specified
idling speed by adjusting the throttle stop
screw. Turn the screw in direction
a to in-
crease the engine speed, and in direction
b
to decrease the engine speed.
Specified idle speed:
1,450–1,550 r/min
U5YT60.book Page 41 Friday, December 12, 2003 1:55 PM

8-43 1. Locknut 2. Adjusting bolt
a. Throttle lever free play
1. Contre-écrou 2. Boulon de réglage
a. Jeu du levier d’accélération
1. Contratuerca 2. Perno de ajuste
a. Juego libre de la palanca del acelerador
EBU00307
Throttle lever adjustmentNOTE:Adjust the engine idling speed before adjusting the
throttle lever free play.1. Loosen the locknut.
2. Turn the adjusting bolt until the throttle lever
free play is 2–4 mm.
3. Tighten the locknut.
EBU00303
Valve clearance adjustment
The correct valve clearance changes with use, re-
sulting in improper fuel/air supply or engine noise.
To prevent this, the valve clearance must be ad-
justed regularly. This adjustment however, should
be left to a professional Yamaha service techni-
cian.
U5YT60.book Page 43 Friday, December 12, 2003 1:55 PM

8-71 1. O-rings
1. Joints toriques
1. Juntas tóricas
EBU00805
Lubricating the drive chain
The drive chain must be cleaned and lubricated at
the intervals specified in the periodic maintenance
and lubrication chart, otherwise it will quickly wear
out, especially when riding in dusty or wet areas.
Service the drive chain as follows.CAUTION:_ The 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:_ To 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:_ 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. _
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8-73
EBU00570
Cable inspection and lubrication
WARNING
Inspect cables frequently and replace if dam-
aged. Corrosion can result when the outer cov-
ering of control cables becomes damaged.
Cables can also become frayed or kinked. Op-
eration of controls could be restricted, which
could cause an accident or injury.Lubricate the inner cables and the cable ends. If
the cables do not operate smoothly, ask a Yamaha
dealer to replace them.
EBU00737
Brake and shift pedal/brake and clutch lever lu-
brication
Lubricate the pivoting parts of each lever and pedal.Recommended lubricant:
Engine oil
Recommended lubricant:
Lithium-soap-based grease
(all-purpose grease)
U5YT60.book Page 73 Friday, December 12, 2003 1:55 PM

8-107
EBU00440
Troubleshooting chart1. Fuel
Check if there is fuel
in the fuel tank.There is fuel.Turn the fuel cock
lever to “OFF”.No fuel.Fuel cock is
clogged.
Clean the
fuel cock. Some fuel.Turn the fuel cock
lever to “RES”.Restart the engine.
No fuel.Supply fuel.
2. Compression
Use the electric
starter to see if
there is compression.There is compression.
Compression normal.
No compression.Ask a Yamaha dealer to
inspect.
3. Ignition
Remove the
spark plug and
check the electrodes.WetWipe clean with dry cloth.
DryAttach spark plug cap and
ground to chassis.Use the
electric starter.Spark is good.Ignition system is
normal.
Spark is weak.
Adjust the spark plug gap
or replace the spark plug. No spark.
Ask a Yamaha dealer to
inspect. 4. Battery
Use the electric starter.Engine turns over
quickly.Battery is good.
Engine turns over
slowly.Check the battery lead connections,
and charge the battery if necessary.Check the
fuel flow.
Turn the fuel cock
lever to “ON”.
Remove the fuel hose
from the fuel cock.
U5YT60.book Page 107 Friday, December 12, 2003 1:55 PM

9-1
EBU00418
CLEANING AND STORAGE
A. CLEANING
Frequent, thorough cleaning of your machine will
not only enhance its appearance but will improve
its general performance and extend the useful life
of many components.
1. Before cleaning the machine:
a. Block off the end of the exhaust pipe to pre-
vent water entry. A plastic bag and strong
rubber band may be used.
b. Make sure the spark plug and all filler caps
are properly installed.
2. If the engine case is excessively greasy, ap-
ply degreaser with a paint brush. Do not ap-
ply degreaser to the chain, sprockets or
wheel axles.
3. Rinse the dirt and degreaser off with a garden
hose. Use only enough pressure to do the
job.
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9-5
8. Automotive type wax may be applied to all
painted and chrome plated surfaces. Avoid
combination cleaner-waxes. Many contain
abrasives which may mar the paint or protec-
tive finish. When finished, start the engine
and let it idle for several minutes.
WARNING
Wet brakes may have reduced stopping ability,
increasing the chance of an accident. Test the
brakes after washing. Apply the brakes several
times at slow speeds to let friction dry out the
linings.
U5YT60.book Page 5 Friday, December 12, 2003 1:55 PM

9-7
EBU00526
B. STORAGE
Long term storage (60 days or more) of your ma-
chine will require some preventive procedures to
guard against deterioration. After thoroughly
cleaning the machine, prepare for storage as fol-
lows:
1. Fill the fuel tank with fresh fuel and add fuel
stabilizer (if available).NOTE:Use of fuel stabilizer eliminates the need to drain
the fuel system. Consult a Yamaha dealer if the
fuel system is to be drained instead.2. Remove the spark plug, pour about one ta-
blespoon of SAE 10W30 or 20W40 motor oil
in the spark plug hole and reinstall the spark
plug. Ground the spark plug wire and turn the
engine over several times to coat the cylinder
wall with oil.
3. Clean the drive chain thoroughly and lubri-
cate it. (See page 8-71.)
4. Lubricate all control cables.
U5YT60.book Page 7 Friday, December 12, 2003 1:55 PM