2002 YAMAHA WR 426F oil level

3 - 18
INSP
ADJ
PILOT SCREW ADJUSTMENT
10. Install:
Oil filler plug
11. Inspect:
Engine (for oil leaks)
Oil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”.
12. Check:
Oil pressure
PILOT SCREW ADJUSTMENT
1. Adjust:
Pilot screw 1
* Except for USAChecking steps:
Slightly loosen the oil gallery bolt 1.
Start the engine and keep it idling until oil
starts to seep from the oil gallery bolt. If no
oil comes out after one minute, turn the
engine off so it will not seize.
Check oil passages, oil filter and oil pump
for damage or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten the oil gallery bolt to specification.
T R..
Oil gallery bolt:
18 Nm (1.8 m • kg, 13 ft • lb)
Adjusting steps:
NOTE:
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 num-
ber as the factory-set number of turns out.
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the factory-set
number of turns.
Pilot screw:
WR426F: 1-5/8 turns out
* 1-1/8 turns out
WR400F: 1-1/2 turns out
(example)

4 - 65
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
REMOVAL POINTS
EC4G3110
Impeller shaft
1. Remove:
Impeller 1
Plain washer 2
Impeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats a with spanners, etc. and remove the
impeller.
EC4G3210
Oil seal
NOTE:
It is not necessary to disassemble the water
pump, unless there is an abnormality such as
excessive change in coolant level, discolora-
tion of coolant, or milky transmission oil.
1. Remove:
Bearing 1
Oil seal 2
INSPECTION
EC444200
Impeller shaft
1. Inspect:
Impeller shaft 1
Bend/wear/damage → Replace.
Fur deposits → Clean.

5 - 26
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake hose holder 1
Screw (brake hose holder) 2
CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
Brake fluid
1. Fill:
Brake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
Use only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
Refill with the same type of brake fluid;
mixing fluids may result in a harmful chem-
ical reaction and lead to poor performance.
Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
ÅFront
ıRear
Recommended brake fluid:
DOT #4
Å
ı

5 - 37
CHASFRONT FORK
19. Wait ten minutes until the air bubbles
have been removed from the front fork,
and the oil has dispense evenly in system
before setting recommended oil level.
NOTE:
Fill with the fork oil up to the top end of the
outer tube, or the fork oil will not spread over to
every part of the front forks, thus making it
impossible to obtain the correct level.
Be sure to fill with the fork oil up to the top of
the outer tube and bleed the front forks.
20. Measure:
Oil level (left and right) a
Out of specification → Adjust.
* For EUROPE
NOTE:
Be sure to install the spring guide 2 when
checking the oil level.
WARNING
Never fail to make the oil level adjustment
between the maximum and minimum level
and always adjust each front fork to the
same setting. Uneven adjustment can
cause poor handling and loss of stability.
Standard oil level:
135 mm (5.31 in)
*125 mm (4.92 in)
Extent of adjustment:
80 ~ 150 mm (3.15 ~ 5.91 in)
From top of outer tube with
inner tube and damper rod 1
fully compressed without
spring.

7 - 13
TUNSETTING
EC722011
Front fork setting
The front fork setting should be made depend-
ing on the rider’s feeling of an actual run and
the circuit conditions.
The front fork setting includes the following
three factors:
1. Setting of air spring characteristics
Change the fork oil level.
2. Setting of spring preload
Change the spring.
Install the adjustment washer.
3. Setting of damping force
Change the compression damping.
Change the rebound damping.
The spring acts on the load and the
damping force acts on the cushion
travel speed.
EC723001
Change in level and characteristics of fork
oil
Damping characteristic near the final stroke
can be changed by changing the fork oil
amount.
CAUTION:
Adjust the oil level in 5 mm (0.2 in) incre-
ments or decrements. Too low oil level
causes the front fork to produce a noise at
full rebound or the rider to feel some pres-
sure on his hands or body. Alternatively,
too high oil level will develop unexpectedly
early oil lock with the consequent shorter
front fork travel and deteriorated perfor-
mance an characteristics. Therefore, adjust
the front fork within the specified range.
* For EUROPE
ÅAir spring characteristics in relation to oil level
change
ıLoad
ÇStroke
1Max. oil level
2Standard oil level
3Min. oil level
Standard oil level:
135 mm (5.31 in)
*125 mm (4.92 in)
Extent of adjustment:
80 ~ 150 mm (3.15 ~ 5.91 in)
From top of outer tube with
inner tube and damper rod fully
compressed without spring.
Å

7 - 21
TUNSETTING
EC72H002
Suspension setting
Front fork
NOTE:
If any of the following symptoms is experienced with the standard position as the base, make
resetting by reference to the adjustment procedure given in the same chart.
Before any change, set the rear shock absorber sunken length to the standard figure 90 ~
100 mm (3.5 ~ 3.9 in).
SymptomSection
Check Adjust
JumpLarge
gapMedium
gapSmall
gap
Stiff over entire range

Compression damping
Oil level (oil amount)
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
Replace with soft spring.
Unsmooth movement
over entire range

Outer tube
Inner tube
Under bracket tightening
torqueCheck for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Retighten to specified torque.
Poor initial movement

Rebound damping
Oil sealTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Apply grease in oil seal wall.
Soft over entire range,
bottoming out

Compression damping
Oil level (oil amount)
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Increase oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
Replace with stiff spring.
Stiff toward stroke end
Oil level (oil amount) Decrease oil level by about 5 mm (0.2 in).
Soft toward stroke end,
bottoming out
Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
Stiff initial movement
Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture

Compression damping
Rebound damping
Balance with rear end
Oil level (oil amount)Turn adjuster clockwise (about 2 clicks) to increase
damping.
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 95 ~ 100 mm (3.7 ~ 3.9 in) when
one passenger is astride seat (lower rear posture).
Increase oil level by about 5 mm (0.2 in).
“Obtrusive” front, tend-
ing to upper front pos-
ture

Compression damping
Balance with rear end
Spring
Oil lever (oil amount)Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 90 ~ 95 mm (3.5 ~ 3.7 in) when
one passenger is astride seat (upper rear posture).
Replace with soft spring.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).