engine YAMAHA YFM350R 2012 Owner's Guide

8-1
8
EBU28783
PERIODIC MAINTENANCE AND ADJUSTMENT
EBU21674Periodic inspection, adjustment, and lubrication
will keep your vehicle in the safest and most effi-
cient condition possible. Safety is an obligation of
the vehicle owner/operator. The most important
points of vehicle inspection, adjustment, and lubri-
cation are explained on the following pages.
WARNING
EWB01841Failure to properly maintain the vehicle or per-
forming maintenance activities incorrectly may
increase your risk of injury or death during ser-
vice or while using the vehicle. If you are not fa-
miliar with vehicle service, have a Yamaha
dealer perform the service.
WARNING
EWB02562Turn off the engine when performing mainte-
nance unless otherwise specified.
A running engine has moving parts that can
catch on body parts or clothing and electri-
cal parts that can cause shocks or fires.

Running the engine while servicing can lead
to eye injury, burns, fire, or carbon monoxide
poisoning - possibly leading to death. See
page 2-3 for more information about carbon
monoxide.
WARNING
EWB02690Brake discs, calipers, drums, and linings can
become very hot during use. To avoid possible
burns, let brake components cool before
touching them.The intervals given in the periodic maintenance
charts should be considered as a general guide
under normal riding conditions. However, DE-
PENDING ON THE WEATHER, TERRAIN, GEO-
GRAPHICAL LOCATION, AND INDIVIDUAL
USE, THE MAINTENANCE INTERVALS MAY
NEED TO BE SHORTENED.
U1BS62E0.book Page 1 Monday, April 18, 2011 6:43 PM

8-3
8
EBU21743Periodic maintenance chart for the emission control system TIP
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 inter-
vals. However, keep in mind that if the ATV isn’t used for a long period of time, the month maintenance
intervals should be followed.
Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills.NO. ITEM CHECK OR MAINTENANCE
JOB INITIAL
EVERY
Whichev- er comes first month136612
km
(mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320
1 *Fuel line 
Check fuel hoses for cracks or other damage, and
replace if necessary. √√√
2 Spark plug 
Check condition and clean, regap, or replace if
necessary. √√√√√
3 *Valves Check valve clearance and adjust if necessary. √ √√√
4 *Carburetor 
Check starter (choke) operation and correct if nec-
essary.
 Check engine idling speed and adjust if neces-
sary. √√√√
5 *Crankcase breather
system 
Check breather hose for cracks or other damage,
and replace if necessary. √√√
U1BS62E0.book Page 3 Monday, April 18, 2011 6:43 PM

8-7
8
14*Chassis fasteners 
Make sure that all nuts, bolts, and screws are
properly tightened. √√√√√
15 *Shock absorber as-
semblies 
Check operation and correct if necessary.
 Check for oil leakage and replace if necessary. √√√
16 *Rear suspension re-
lay arm and con-
necting arm
pivoting points 
Check operation and correct if necessary.
 Lubricate with lithium-soap-based grease. √√√√
17 *Steering shaft Lubricate with lithium-soap-based grease. √√√
18 *Steering system 
Check operation and repair or replace if damaged.
 Check toe-in and adjust if necessary. √√√√√
19 Engine oil 
Change.
 Check ATV for oil leakage, and correct if neces-
sary. √ √√√
20 Engine oil filter ele-
ment 
Clean or replace if necessary. √√√
21 Engine oil strainer Clean. √√√
22 *Moving parts and
cables 
Lubricate. √√√√
NO. ITEM
CHECK OR MAINTENANCE
JOB INITIAL EVERY
Whichev- er comes first month136612
km
(mi) 320
(200) 1300
(800) 2500
(1600) 2500
(1600) 5000
(3200)
hours 20 80 160 160 320U1BS62E0.book Page 7 Monday, April 18, 2011 6:43 PM

8-9
8
EBU23213Checking the spark plug The spark plug is an important engine component,
which is easy to check. Since heat and deposits
will cause any spark plug to slowly erode, the spark
plug should be removed and checked in accor-
dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
To remove the spark plug1. Remove the spark plug cap. 2. Remove the spark plug as shown, with the
spark plug wrench included in the owner ’s tool
kit.
To check the spark plug 1. Check that the porcelain insulator around the center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).1. Spark plug cap
1. Spark plug wrench
U1BS62E0.book Page 9 Monday, April 18, 2011 6:43 PM

8-10
8
TIPIf the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.2. Check the spark plug for electrode erosionand excessive carbon or other deposits, and
replace it if necessary.
3. Measure the spark plug gap with a wire thick- ness gauge and, if necessary, adjust the gap
to specification.
To install the spark plug1. Clean the surface of the spark plug gasket and its mating surface, and then wipe off any
grime from the spark plug threads.
2. Install the spark plug with the spark plug wrench, and then tighten it to the specified
torque.
Specified spark plug:
NGK/DR8EA
1. Spark plug gapSpark plug gap:0.6 –0.7 mm (0.024 –0.028 in)
U1BS62E0.book Page 10 Monday, April 18, 2011 6:43 PM

8-11
8
TIPIf a torque wrench is not available when installing
the spark plug, a good estimate of the correct
torque is 1/4–1/2 turn past finger tight. However,
the spark plug should be tightened to the specified
torque as soon as possible.3. Install the spark plug cap.EBU2327EEngine oil and oil filter element The engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter element cleaned at the intervals speci-
fied in the periodic maintenance and lubrication
chart.
To check the engine oil level 1. Place the ATV on a level surface.
2. Check the engine oil level on a cold engine.
TIPIf the engine was started before checking the oil
level, be sure to warm up the engine sufficiently,
and then wait at least ten minutes until the oil set-
tles for an accurate reading.3. Remove the engine oil filler cap, and then wipe the engine oil dipstick off with a clean
rag.
4. Insert the dipstick into the filler hole (without screwing it in), and then remove it again to
check the oil level.TIPThe engine oil should be between the minimum
and maximum level marks.
Tightening torque:Spark plug:18 Nm (1.8 m ·kgf, 13 ft ·lbf)
U1BS62E0.book Page 11 Monday, April 18, 2011 6:43 PM

8-12
85. 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.
NOTICE: Be sure the engine oil is at the
correct level, otherwise engine damage
may result.
[ECB00851]
6. Insert the dipstick into the oil filler hole, and then tighten the engine oil filler cap. To change the engine oil (with or without oil fil-
ter element cleaning)
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. Place an oil pan under the engine to collect the used oil.
4. Remove the engine oil filler cap, and then re- move the engine oil drain bolt to drain the oil
from the crankcase. NOTICE: When remov-
ing the engine oil drain bolt, the compres-
sion spring, oil strainer and O-ring will fall
out. Take care not to lose these parts.
[ECB00311]
1. Engine oil dipstick
2. Maximum level mark
3. Minimum level mark
4. Engine oil filler capU1BS62E0.book Page 12 Monday, April 18, 2011 6:43 PM

8-13
8
TIPSkip steps 5–9 if the oil filter element is not being
cleaned.5. Remove the oil filter element cover by remov- ing the bolts, and then remove the oil filter el-
ement and the O-ring. 6. Clean the oil strainer and oil filter element with
solvent.
7. Install the oil filter element and a new O-ring.
TIPMake sure that the O-ring is properly seated.8. Apply a thin coat of clean engine oil to the O- ring.
9. Install the oil filter element cover by installing the bolts, and then tighten them to the speci-
fied torque.
1. Engine oil drain bolt
2. O-ring
3. Compression spring
4. Oil strainer
1. Oil filter element cover
2. Bolt
3. Oil filter element
4. O-ring
U1BS62E0.book Page 13 Monday, April 18, 2011 6:43 PM

8-14
810. Apply a thin coat of clean engine oil to a new
O-ring.
11. Install the oil strainer, the compression spring, the new O-ring and the engine oil drain bolt.
Tighten the engine oil drain bolt to the speci-
fied torque. NOTICE: Before installing the engine oil drain bolt, be sure to install the
O-ring, compression spring and oil strain-
er.
[ECB00321]
12. Refill with the specified amount of the recom-
mended engine oil, and then install and tight-
en the engine oil filler cap.TIPBe sure to wipe off spilled oil on any parts after the
engine and exhaust system have cooled down.
Tightening torque:Oil filter element cover bolt:10 Nm (1.0 m ·kgf, 7.2 ft ·lbf)1. Engine oil drain bolt
2. O-ring
3. Compression spring
4. Oil strainer
Tightening torque:
Engine oil drain bolt:32 Nm (3.2 m ·kgf, 23 ft· lbf)
Recommended oil: See page 10-1.
Oil quantity: Without oil filter element replacement:2.50 L (2.64 US qt, 2.20 Imp.qt)
With oil filter element replacement: 2.60 L (2.75 US qt, 2.29 Imp.qt)
U1BS62E0.book Page 14 Monday, April 18, 2011 6:43 PM

8-15
8
NOTICEECB00300
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 CONSERV-
ING II ” or higher.
Make sure that no foreign material enters the
crankcase.13. Start the engine, and then let it idle for several
minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
14. Turn the engine off, wait at least ten minutes, and then check the oil level and correct it if
necessary.EBU23743Cleaning the air filter element The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean or, if necessary, replace
the air filter element more frequently if you are
riding in unusually wet or dusty areas.
TIPThere is a check hose at the bottom of the air filter
case. If dust or water collects in this hose, empty
the hose and clean the air filter element and air fil-
ter case.1. Place the ATV on a level surface.
2. Remove the seat. (See page 4-12.)
3. Remove the air filter case cover by unhookingthe holders.1. Air filter case check hose
U1BS62E0.book Page 15 Monday, April 18, 2011 6:43 PM