2005 YAMAHA BRUIN 350 engine

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. Engine compression will do most of
the braking for you. For maximum engine com-
pression braking effect, change to 4WD before be-
ginning to descend the hill. Improper braking may
cause a loss of traction.
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.
When this ATV is in 4WD, all wheels (front and
rear) are interconnected by the drive train. This
means that applying either the front brake or the
rear brake will brake all wheels. When descending
hills, using either brake lever or the brake pedal
will brake the wheels on the downhill side. Avoid
sudden application of either the front or rear brake
because the wheels on the uphill side could come
off the ground. Apply both the front and rear
brakes gradually.
U5UH61.book Page 55 Tuesday, April 20, 2004 10:10 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.
U5UH61.book Page 1 Tuesday, April 20, 2004 10:10 AM

8-7
EBU02621
PERIODIC MAINTENANCE/LUBRICATION
NOTE:_

For ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.


For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance intervals. How-
ever, keep in mind that if the ATV isn’t used for a long period of time, the month maintenance intervals should be
followed.
_
ITEM ROUTINEWhichever
comes firstINITIAL EVERY
month136612
km
(mi)320
(200)1,200
(750)2,400
(1,500)2,400
(1,500)4,800
(3,000)
hours 20 75 150 150 300
Valves*Check valve clearance.
Adjust if necessary.
Spark plugCheck 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 and adjust 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 cartridge
Replace.U5UH61.book Page 7 Tuesday, April 20, 2004 10:10 AM

8-8
Engine oil strainer*
Clean.Final gear oil
Check oil level/oil leakage.
Replace every 12 months.Differential gear oil
Front brake*Check operation/fluid leakage. (See NOTE page 8-9.)
Correct if necessary.Rear brakeCheck operation.
Adjust if necessary.Select lever safety system
cable*Check operation.
Adjust if necessary.V-belt*Check operation.
Check for cracks or damage.Wheels*Check balance/damage/runout.
Repair if necessary.Wheel bearing*Check bearing assemblies for looseness/damage.
Replace if damaged.Front and rear
suspension*Check operation.
Correct if necessary.Steering system*Check operation./Replace if damaged.
Check toe-in./Adjust if necessary.Drive shaft universal
joint*Lubricate with lithium-soap-based grease.Axle boots*Check operation.
Replace if damaged.Fittings and fasteners*Check all chassis fittings and fasteners.
Correct if necessary.
ITEM ROUTINEWhichever
comes firstINITIAL EVERY
month136612
km
(mi)320
(200)1,200
(750)2,400
(1,500)2,400
(1,500)4,800
(3,000)
hours 20 75 150 150 300
U5UH61.book Page 8 Tuesday, April 20, 2004 10:10 AM

8-21 1. Engine oil filler cap
1. Bouchon de remplissage d’huile de moteur
1. Tapa de relleno de aceite de motor
1. Maximum level mark 2. Minimum level mark
1. Repère de niveau maximum 2. Repère de niveau minimum
1. Marca de nivel máximo 2. Marca de nivel mínimo
EBU14540
Engine oil and oil filter cartridge
The engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter cartridge replaced at the intervals
specified in the periodic maintenance and lubrica-
tion chart.
To check the engine oil level
1. Place the ATV on a level surface.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Wait a few minutes until the oil settles.
4. Remove the engine oil filler cap and wipe off
the dipstick with a clean rag.
5. Insert the dipstick in the oil filler hole (without
screwing it in), and then remove it again to
check the oil level.NOTE:_ The engine oil should be between the minimum
and maximum level marks. _
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8-23 1. Engine oil drain bolt
1. Boulon de vidange de l’huile
1. Perno de drenaje del aceite de motor
6. If the engine oil is at or below the minimum
level mark, add sufficient oil of the recom-
mended type to raise it to the correct level.
7. Insert the dipstick into the oil filler hole, and
then tighten the oil filler cap.
To change the engine oil (with or without oil fil-
ter cartridge replacement)
1. Start the engine, warm it up for several min-
utes, and then turn it off.
2. Place an oil pan under the engine to collect
the used oil, and then remove the engine oil
filler cap.
3. Remove the engine oil drain bolt to drain the
oil from the crankcase.
U5UH61.book Page 23 Tuesday, April 20, 2004 10:10 AM

8-27 1. O-ring
1. Joint torique
1. Junta tórica
1. Torque wrench
1. Clé dynamométrique
1. Llave de apriete
5. Apply a light coat of engine oil to the O-ring of
the new oil filter cartridge.NOTE:_ Make sure the O-ring is seated properly. _6. Install the new oil filter cartridge with an oil fil-
ter wrench, and then tighten it to the specified
torque with a torque wrench.
7. Install the engine oil drain bolt, and then tight-
en it to the specified torque. Tightening torque:
Oil filter cartridge:
17 Nm (1.7 m·kgf)
Tightening torque:
Engine oil drain bolt:
23 Nm (2.3 m·kgf)
U5UH61.book Page 27 Tuesday, April 20, 2004 10:10 AM

8-29
8. Add the specified amount of recommended
engine oil, and then install the engine oil filler
cap and tighten it.CAUTION:_

In order to prevent clutch slippage (since
the engine oil also lubricates the clutch),
do not mix any chemical additives. Do not
use oils with a diesel specification of “CD”
or oils of a higher quality than specified. In
addition, do not use oils labeled “ENERGY
CONSERVING II” or higher.


Make sure that no foreign material enters
the crankcase.
_
Recommended engine oil:
See page 10-2.
Oil quantity:
Without oil filter cartridge replacement:
2.2 L
With oil filter cartridge replacement:
2.3 L
U5UH61.book Page 29 Tuesday, April 20, 2004 10:10 AM