YAMAHA YFM90R 2009 Manual Online

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The air filter needs more frequent service if you are riding in unusually wet or dusty areas.
Hydraulic brake service Regularly check and, if necessary, correct the brake fluid level.Every two years replace the internal components of the brake master cylinder and caliper, and
change the brake fluid. Replace the brake hoses every four years and if cracked or damaged.

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Checking the spark plugThe 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 thespark plug wrench included in the owner’s tool
kit.
1. Spark plug cap
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To check the spark plug1. 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).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 erosion and excessive carbon or other deposits, and replace it if necessary.
To install the spark plug 1. Measure the spark plug gap with a wire thick- ness gauge and, if necessary, adjust the gap
to specification.1. Spark plug wrench
Specified spark plug:NGK/CR7HSA
Spark plug gap: 0.6–0.7 mm (0.024–0.028 in)1. Spark plug gap
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2. Clean the surface of the spark plug gasketand its mating surface, and then wipe off any
grime from the spark plug threads.
3. Install the spark plug with the spark plug wrench, and then tighten it to the specified
torque.TIPIf a torque wrench is not available when installing
a 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 assoon as possible.
4. Install the spark plug cap. Engine oil The engine oil level should be checked before
each ride. In addition, the oil must be changed at
the intervals specified 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-1. Engine oil filler cap
2. Dipstick
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tles for an accurate reading.
3. Remove the engine oil filler cap, and then wipe the dipstick off with a clean rag.
Tightening torque:
Spark plug:12.0 Nm (1.20 m·kgf, 8.9 ft·lbf)
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4. Insert the dipstick into the filler hole (withoutscrewing it in), and then remove it again to
check the oil level.TIPThe engine oil should be between the minimumand maximum level marks.
5. 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.
6. Insert the dipstick into the oil filler hole, and then tighten the engine oil filler cap.1. Maximum level mark
2. Minimum level mark
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To change the engine oil 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 remove the engine oil drain bolt to drain the
oil from the crankcase.
5. Check the washer for damage and replace it if necessary.
6. Install the engine oil drain bolt, and then tighten it to the specified torque.
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1. Engine oil drain bolt
2. O-ring
3. Spring
4. Oil filter element

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7. Add the specified amount of the recommend-ed engine oil, and then install and tighten the
engine oil filler cap.
Tightening torque:
Engine oil drain bolt:8 Nm (0.8m·kgf, 5.8 ft·lbf)
Recommended oil: See page 10-1.
Oil quantity: 0.8 L (0.84 US qt) (0.70 Imp.qt)N O T I C EDo not mix any chemical additives. Do
not use oils with a diesel specification
of "CD" or oils of a higher quality than
sp eci fi ed . I n ad d i ti o n , d o n o t u se o i ls l ab el e d " E N E R G Y C O N S E R V I N G I I " o r
higher.the crankcase.
8. Start the engine, and then let it idle for severalMake sure that no foreign material enters minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
9. Turn the engine off, wait at least ten minutes, and then check the oil level and correct it if
necessary.

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1. Final transmission oil ller cap
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1. Final transmission oil drain bolt
4. Install the drain bolt, and then tighten it to thespecified torque.Final transmission oil The final transmission case must be checked for
oil leakage before each ride. If any leakage isfound, have a Yamaha dealer check and repair theATV. In addition, the final transmission oil must be
changed at the intervals specified in the periodic
maintenance and lubrication chart.
1. Place the ATV on a level surface.
2. Place an oil pan under the final transmission.
3. Remove the final transmission oil filler cap and the drain bolt to drain the oil from the final
transmission oil case.
To change the final transmission oil

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Tightening torque:Final transmission oil drain bolt:15 Nm (1.5 m·kgf, 10.8 ft·lbf)5. Add the specified amount of the recommend- ed final transmission oil, and then check the
oil level.N O T I C E Be sure no foreign material enters the final
transmission case.
6. Install and tighten the oil filler cap.
7. Check the final transmission case for oil leakage. If oil is leaking, check for the cause.
Recommended final transmission oil:
See page 10-1.
Oil quantity: 0.30 L (0.32 US qt) (0.27 Imp.qt)
Cleaning the air filter element The air filter element should be cleaned at the in-
tervals specified in the periodic maintenance and
lubrication chart. Clean the air filter element more
frequently if you are riding in unusually wet or dusty
areas.TIPThere are check hoses at the bottom of the air filter
case. If dust or water collects in these hoses, empty1. Air filter case check hose (left)
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them and clean the air filter element and air filter
case.

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1. Remove the air filter case cover by remov-
ing the bolts.
1. Air filter case cover (left)
2. Bolts
1. Air filter case check hose (right)
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1. Air filter case cover (right)
2. Bolts
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N O T I C EDo not twist the sponge material when squeez-ing it.5. Check the sponge material and replace it if damaged.
1. Air filter element holder
2. Sponge material
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2. Remove the air filter element by removing the
3. Wash the sponge material gently but thor- oughly in solvent. 4. Squeeze the excess solvent out of the sponge
material and let it dry.
screw, and then pull off the sponge material
from the air filter element holder.
WARNING
Always use parts cleaning solvent to clean the
sponge material. Never use low-flash-point
solvents or gasoline to clean the sponge mate- rial because the engine could catch fire or ex-
plode.