
3-8
ENGINE
d. Tighten the locknut.
Before adjusting the throttle cable
free play, the engine idle speed
should be adjusted.
After adjusting the throttle cable
free play, start the engine and turn
the handlebar to right and left and
make sure that the engine idling
does not run faster.
LUBRICATING THE THROTTLE
1. Remove:
• Cover (throttle cable cap) "1"
• Cover (grip cap) "2"
• Throttle grip cap "3"
2. Apply:
• Lithium soap base grease
On the throttle cable end "a".
3. Install:
• Throttle grip cap
• Screw (throttle grip cap)
• Cover (grip cap)
• Cover (throttle cable cap)ADJUSTING THE HOT STARTER
LEVER FREE PLAY
1. Check:
• Hot starter lever free play "a"
Out of specification→Adjust.
2. Adjust:
• Hot starter lever free play
Hot starter lever free play adjust-
ment steps:
a. Loosen the locknut "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknut.
After adjustment, check proper oper-
ation of hot starter.
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Remove:
•Seat
• Fitting bolt "1"
•Washer "2"
• Air filter element "3"
• Air filter guide "4"2. Clean:
• Air filter element
Clean them with solvent.
After cleaning, remove the remaining
solvent by squeezing the element.
• Do not twist the element when
squeezing the element.
• Leaving too much of solvent in
the element may result in poor
starting.
3. Inspect:
• Air filter element
Damage→Replace.
4. Apply:
• Foam-air-filter oil or equivalent oil
to the element
Squeeze out the excess oil. Element
should be wet but not dripping.
5. Install:
• Air filter guide "1"
Align the projection "a" on filter guide
with the hole "b" in air filter element.
6. Apply:
• Lithium soap base grease
On the matching surface "a" on air
filter element. Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Screw (throttle grip cap):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Hot starter lever free play
"a":
3–6 mm (0.12–0.24 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)

3-9
ENGINE
7. Install:
• Air filter element "1"
• Washer
• Fitting bolt
Align the projection "a" on filter guide
with the hole "b" in air filter case.
CHECKING THE ENGINE OIL
LEVEL
1. Stand the machine on a level sur-
face.
• When checking the oil level make
sure that the machine is upright.
• Place the machine on a suitable
stand.
Never remove the oil tank cap just
after high speed operation. The
heated oil could spurt out. causing
danger. Wait until the oil cools
down to approximately 70°C
(158°F).
2. Idle the engine more than 3 min-
utes while keeping the machine
upright. Then stop the engine and
inspect the oil level.
3. Remove:
• Oil tank cap 14. Inspect:
• Oil level
Check that the engine oil is above
the level mark "a" and that the oil
does not come out when the
check bolt "1" is removed.
Below the level mark "a"→Add oil
through the filler cap hole until it is
above the level mark "a".
Oil comes out at the check bolt→
Drain the oil until it stops coming
out.
When inspecting the oil level, do not
screw the oil level gauge into the oil
tank. Insert the gauge lightly.
• Engine oil also luburicates the
clatch and the wrong oil types or
additives could cause clatch
slippage. Therefore, do not oils
with a grade of CD "a" or higher
and do not use oils labeled "EN-
ERGY CONSERVING II" "b" .
• Do not allow foreign material to
enter the crankcase.
(For USA and CDN)(Except for USA and CDN)
5. Start the engine and let it warm up
for several minutes.
When the oil tank is empty, never
start the engine.
6. Idle the engine more than 10 sec-
onds while keeping the machine
upright. Then stop the engine and
add the oil to the maximum level.
7. Install:
• Oil tank cap
CHANGING THE ENGINE OIL
1. Start the engine and let it warm up
for several minutes.
2. Stop the engine and place an oil
pan under the drain bolt.
3. Remove:
• Oil tank plug "1"
• Oil filler cap "2"
• Drain bolt (with gasket) "3"
• Oil filter drain bolt (O-ring) "4"
• Drain bolt (with gasket) "5"
Drain the crankcase and oil tank
of its oil. Fitting bolt:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Recommended oil:
Yamalube 4, SAE10W-
40 or SAE20W-50
Yamalube 4-R,
SAE10W-50
API service SG type or
higher, JASO standard
MA
4
Recommended oil:
SAE10W-30, SAE10W-
40, SAE15W-40,
SAE20W-40 or
SAE20W-50
API service SG type or
higher, JASO standard
MA

3-10
ENGINE
4. If the oil filter is to be replaced dur-
ing this oil change, remove the fol-
lowing parts and reinstall them.
Replacement steps:
a. Remove the oil filter element cov-
er "1" and oil filter element "2".
b. Check the O-rings "3", if cracked
or damaged, replace them with a
new one.
c. Install the oil filter element and oil
filter element cover.
5. Install:
• Gaskets
• Oil filter drain bolt
• Drain bolt (right crankcase)
• Drain bolt (left crankcase)6. Fill:
• Engine oil
7. Install:
• Oil filler cap
8. Inspect:
• Engine (for oil leaks)
• Oil level
Refer to "ENGINE OIL LEVEL IN-
SPECTION".
CHECKING THE OIL PRESSURE
1. Check:
• Oil pressure
Checking steps:
a. Slightly loosen the oil pressure
check bolt "1".
b. Start the engine and keep it idling
until oil starts to seep from the oil
pressure check bolt. If no oil
comes out after one minute, turn
the engine off so it will not seize.
c. Check oil passages and oil pump
for damage or leakage.
d. Start the engine after solving the
problem(s) and recheck the oil
pressure.
e. Tighten the oil pressure check
bolt.
ADJUSTING THE PILOT SCREW
1. Adjust:
•Pilot screw "1"
Adjustment steps:
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
screw has been individually set at the
factory. Before adjusting the pilot
screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Adjust the pilot screw.
Refer to "ADJUSTING THE PI-
LOT SCREW" section.
b. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
Oil filter element cover:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil filter drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Drain bolt (right crank-
case):
20 Nm (2.0 m•kg, 14
ft•lb)
Drain bolt (left crank-
case):
20 Nm (2.0 m•kg, 14
ft•lb)
Oil quantity:
Periodic oil change:
0.95 L (0.84 Imp qt,
1.00 US qt)
With oil filter replace-
ment:
1.0 L (0.88 Imp qt, 1.06
US qt)
Total amount:
1.2 L (1.06 Imp qt, 1.27
US qt)
Oil pressure check bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Pilot screw (example):
1-1/2 turns out
Digital tachometer:
YU-39951-B/90890-
06760
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed→Turn the
throttle stop screw "1" out "b".

4-33
OIL FILTER ELEMENT AND WATER PUMP
OIL FILTER ELEMENT AND WATER PUMP
REMOVING THE OIL FILTER ELEMENT AND WATER PUMP
Order Part name Q'ty Remarks
Right engine guard Refer to "ENGINE REMOVAL" section.
Drain the engine oil. Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Drain the coolant. Refer to "CHANGING THE COOLANT" sec-
tion.
Exhaust pipe Refer to "EXHAUST PIPE AND SILENCER"
section.
Brake pedal Refer to "ENGINE REMOVAL" section.
Clutch cover Refer to "CLUTCH" section.
1 Oil filter element cover 1
2 Oil filter element 1
3 Coolant pipe 2 1
4 Water pump housing 1
5Pin 2
6 Oil tank breather hose 1
7 Kickstarter crank 1
8 Right crankcase cover 1
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
33 Nm (3.3 m kg, 24 ft lb)
14 Nm (1.4 m kg, 10 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)

4-34
OIL FILTER ELEMENT AND WATER PUMP
9Gasket 1
10 Dowel pin/O-ring 3/1
11 Impeller 1 Refer to removal section.
12 Washer 1 Refer to removal section.
13 Impeller shaft 1 Refer to removal section.
14 Oil seal 1 1 Refer to removal section.
15 Oil seal 2 1 Refer to removal section.
16 Bearing 1 Refer to removal section. Order Part name Q'ty Remarks
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
10 Nm (1.0 m kg, 7.2 ft lb)
33 Nm (3.3 m kg, 24 ft lb)
14 Nm (1.4 m kg, 10 ft lb)
12 Nm (1.2 m kg, 8.7 ft lb)

4-35
OIL FILTER ELEMENT AND WATER PUMP
REMOVING THE IMPELLER
SHAFT
1. Remove:
•Impeller "1"
• Washer "2"
• Impeller shaft "3"
Hold the impeller shaft on its width
across the flats "a" with spanners,
etc. and remove the impeller.
REMOVING THE OIL SEAL
It is not necessary to disassemble the
water pump, unless there is an abnor-
mality such as excessive change in
coolant level, discoloration of coolant,
or milky transmission oil.
1. Remove:
• Bearing "1"
•Oil seal "2"
CHECKING THE IMPELLER SHAFT
1. Inspect:
• Impeller shaft "1"
Bend/wear/damage→Replace.
Fur deposits→Clean.CHECKING THE BEARING
1. Inspect:
• Bearing
Rotate inner race with a finger.
Rough spot/seizure→Replace.
CHECKING THE OIL SEAL
1. Inspect:
• Oil seal "1"
Wear/damage→Replace.
INSTALLING THE OIL SEAL
1. Install:
• Oil seal "1"
• Apply the lithium soap base grease
on the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or numbers facing the
right crankcase cover "2".
2. Install:
• Bearing "1"
Install the bearing by pressing its out-
er race parallel.
INSTALLING THE IMPELLER
SHAFT
1. Install:
• Impeller shaft "1"
• Washer "2"
• Impeller "3"
• Take care so that the oil seal lip is
not damaged or the spring does not
slip off its position.
• When installing the impeller shaft,
apply the engine oil on the oil seal
lip, bearing and impeller shaft. And
install the shaft while turning it.
• Hold the impeller shaft on its width
across the flats "a" with spanners,
etc. and install the impeller.
INSTALLING THE RIGHT
CRANKCASE COVER
1. Install:
• Dowel pin "1"
• O-ring "2"
•Collar "3"
• Gasket "4"
Apply the lithium soap base grease
on the O-ring.
Impeller:
14 Nm (1.4 m•kg, 10
ft•lb)

4-36
OIL FILTER ELEMENT AND WATER PUMP
2. Install:
• Right crankcase cover "1"
•Bolt "2"
•Bolt
• Apply the engine oil on the impeller
shaft end.
• When installing the crankcase cov-
er onto the crankcase, be sure that
the impeller shaft end "2" aligns
with the balancer end slot "3".
• Tighten the bolts in stage, using a
crisscross pattern.
INSTALLING THE KICKSTARTER
CRANK
1. Install:
• Kickstarter crank "1"
• Washer
• Bolt (kickstarter crank)
Install so that there is a clearance "a"
of 8 mm (0.31 in) or more between
the kickstarter and frame and that the
kickstarter does not contact the
crankcase cover when it is pulled.
2. Install:
• Oil tank breather hose "1"
•Clamp "2"
INSTALLING THE WATER PUMP
HOUSING
1. Install:
• Dowel pin "1"
• O-ring "2"
Apply the lithium soap base grease
on the O-ring.
2. Install:
• Water pump housing "1"
• Bolt (water pump housing) "2"
• Washer "3"
• Coolant drain bolt "4"3. Install:
• O-ring
• Coolant pipe "1"
• Bolt (coolant pipe) "2"
Apply the lithium soap base grease
on the O-ring.
INSTALLING THE OIL FILTER
ELEMENT
1. Install:
• Oil filter element "1"
• O-ring "2"
• Oil filter element cover "3"
• Bolt (oil filter element cover)
Apply the lithium soap base grease
on the O-ring.
Bolt:
12 Nm (1.2 m•kg, 8.7
ft•lb)
Bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (kickstarter crank):
33 Nm (3.3 m•kg, 24
ft•lb)Clamp:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (water pump hous-
ing):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (coolant pipe):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (oil filter element
cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)

4-37
BALANCER
BALANCER
REMOVING THE BALANCER
Order Part name Q'ty Remarks
Primary driven gear Refer to "CLUTCH" section.
Right crankcase cover Refer to "OIL FILTER ELEMENT AND WA-
TER PUMP" section.
Stator Refer to "CDI MAGNETO" section.
1 Nut (balancer) 1 Refer to removal section.
2 Nut (primary drive gear) 1 Refer to removal section.
3 Nut (balancer shaft driven gear) 1 Refer to removal section.
4 Lock washer 1
5Balancer 1
6 Straight key 1
7 Conical washer 1
8 Primary drive gear 1
9 Balancer shaft drive gear 1
10 Lock washer 1
11 Balancer shaft driven gear 1