2004 YAMAHA WARRIOR 350 engine

7-35
With the engine idling, pull the clutch lever to dis-
engage the clutch and shift into 1st gear, and then
release the parking brake. Open the throttle grad-
ually, and at the same time, release the clutch le-
ver slowly. Once the ATV has attained adequate
speed, release the throttle lever and at the same
time, quickly pull in the clutch lever and shift into
2nd gear. Open the throttle part way and gradually
release the clutch. Use this same procedure as
you move into the higher gears. Be sure to coordi-
nate the use of the throttle and shift pedal properly.
If the throttle is applied too abruptly or if the throttle
is not released during shifting, or if the shift pedal
is not released before applying the throttle, the
front wheels may lift off the ground resulting in a
loss of directional control. Avoid higher speeds un-
til you are thoroughly familiar with the operation of
your ATV.
WARNING
_ Always open the throttle gradually and release
the clutch lever slowly. Otherwise, the ATV
could wheelie which would increase the
chance of an accident. _
U5NF63.book Page 35 Wednesday, March 12, 2003 10:06 AM

7-37
CAUTION:_ Do not shift gears without releasing the throt-
tle. Damage to the engine or drive train may oc-
cur. _When slowing down or stopping, release the throt-
tle and apply the brakes smoothly and evenly. As
you slow down, shift to a lower gear. Be sure that
the engine has sufficiently slowed before engaging
a lower gear. Improper use of the brakes or shift-
ing can cause the tires to lose traction, reducing
control and increasing the possibility of an acci-
dent.
WARNING
_ Make sure the engine has sufficiently slowed
before shifting to a lower gear. Engaging a low-
er gear when the engine speed is too high
could cause the wheels to stop rotating. _
U5NF63.book Page 37 Wednesday, March 12, 2003 10:06 AM

7-55
RIDING DOWNHILL
When riding your ATV downhill, shift your weight
as far to the rear and uphill side of the ATV as pos-
sible. Move back on the seat and sit with your
arms straight. Choose a low gear which will allow
the engine compression to do most of the braking
for you. Improper braking may cause a loss of trac-
tion.
Use caution while descending a hill with loose or
slippery surfaces. Braking ability and traction may
be adversely affected by these surfaces. Improper
braking may also cause a loss of traction.
Whenever possible, ride your ATV straight down-
hill. Avoid sharp angles which could allow the ATV
to tip or roll over. Carefully choose your path and
ride no faster than you will be able to react to ob-
stacles which may appear.
U5NF63.book Page 55 Wednesday, March 12, 2003 10:06 AM

8-1
EBU00516
PERIODIC MAINTENANCE AND
ADJUSTMENTPeriodic inspection, adjustment and lubrication will
keep your machine in the safest and most efficient
condition possible. Safety is an obligation of the
machine owner. The most important points of ma-
chine inspection, adjustment and lubrication are
explained on the following pages.
WARNING
Never service an engine while it is running.
Moving parts can catch clothing or parts of the
body, causing injury. Electrical components
can cause shocks or can start fires. Turn off
the engine when performing maintenance un-
less otherwise specified. Have a Yamaha deal-
er perform service if you are not familiar with
machine service.
U5NF63.book Page 1 Wednesday, March 12, 2003 10:06 AM

8-7
EBU00262
PERIODIC MAINTENANCE/LUBRICATION
ITEM ROUTINEINITIAL EVERY
1
month3
months6
months6
months1
year
Valves*Check valve clearance.
Adjust if necessary.
Spark plug*Check condition.
Adjust gap and clean.
Replace if necessary.Air filter elementClean.
Replace if necessary.Every 20–40 hours
(More often in wet or dusty areas.)
Carburetor*Check idle speed/starter operation.
Adjust if necessary.Crankcase breather
system*Check breather hose for cracks or damage.
Replace if necessary.Exhaust system*Check for leakage.
Tighten if necessary.
Replace gasket(s) if necessary.Fuel line*Check fuel hose for cracks or damage.
Replace if necessary.Engine oil
Replace. (Warm engine before draining.)Engine oil filter elementClean.
Replace if necessary.Engine oil strainer
Clean.Drive chain
Check and adjust slack/alignment/clean/lube.Brakes*Check operation/fluid leakage/See NOTE page 8-8.
Correct if necessary.Clutch*Check operation.
Adjust if necessary.Wheels*Check balance/damage/runout.
Replace if necessary.Wheel bearings*Check bearing assemblies for looseness/damage.
Replace if damaged.U5NF63.book Page 7 Wednesday, March 12, 2003 10:06 AM

8-15 1. Dipstick 2. Maximum level mark
3. Minimum level mark
1. Jauge 2. Repère de niveau maximum
3. Repère de niveau minimum
1. Varilla 2. Marca de nivel máximo
3. Marca de nivel mínimo
EBU01181
Engine oil
Engine oil level measurement
1. Place the ATV on a level surface.
2. Warm up the engine for several minutes, and
then stop it.
3. Remove the engine oil filler cap, and then
wipe the dipstick off with a clean rag. Insert
the dipstick in the filler hole without screwing
it in.NOTE:_ Wait a few minutes until the oil level settles before
checking. _4. Remove the dipstick, and then check the oil
level.NOTE:_ The oil level should be between the maximum and
minimum level marks. _
U5NF63.book Page 15 Wednesday, March 12, 2003 10:06 AM

8-17 1. Engine oil drain bolt 2. O-ring
3. Compression spring 4. Engine oil strainer
1. Boulon de vidange de l’huile moteur
2. Joint torique
3. Ressort de compression
4. Crépine à huile de moteur
1. Perno de drenaje del aceite de motor
2. Junta tórica
3. Muelle de compresión
4. Tamiz de aceite de motor
5. If the engine oil is below the minimum level
mark, add sufficient oil of the recommended
type to raise it to the correct level.CAUTION:_ Be sure no foreign material enters the crank-
case. _6. Insert the dipstick into the oil filler hole, and
then tighten the engine oil filler cap.
Engine oil replacement and oil filter element
cleaning
1. Place the ATV on a level surface.
2. Warm up the engine for several minutes and
stop it.
3. Place a container under the engine to collect
the used oil.
4. Remove the engine oil filler cap, and then re-
move the drain bolt to drain the oil.CAUTION:_ When removing the drain bolt, the compres-
sion spring, oil strainer and O-ring will fall out.
Take care not to lose these parts. _
U5NF63.book Page 17 Wednesday, March 12, 2003 10:06 AM

8-19 1. Engine oil filter cover 2. Bolt (× 3)
3. Engine oil filter element 4. O-ring
1. Couvercle du filtre à huile de moteur 2. Boulon (× 3)
3.Élément du filtre à huile de moteur
4. Joint torique
1. Tapa del filtro de aceite de motor 2. Perno (× 3)
3. Elemento del filtro de aceite de motor
4. Junta tórica
5. Remove the oil filter cover by removing the
bolts and then remove the oil filter element.
6. Clean the oil strainer and oil filter element
with solvent.
7. Check the O-ring for damage and replace it if
necessary.
8. Install the oil filter element and O-ring.
9. Install the oil filter cover by installing the bolts.
10. Install the oil strainer, compression spring, O-
ring and drain bolt. Tighten the drain bolt and
oil filter cover bolts to the specified torques.CAUTION:_ Before installing the drain bolt, be sure to in-
stall the O-ring, compression spring and oil
strainer. _
U5NF63.book Page 19 Wednesday, March 12, 2003 10:06 AM