engine oil YAMAHA WR 426F 2001 User Guide

2 - 11
SPEC

MAINTENANCE SPECIFICATIONS (WR426F)
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M10S
´
1.0 1 13 1.3 9.4
Camshaft cap M6
´
1.0 10 10 1.0 7.2
Cylinder head (stud bolt) M6
´
1.0 2 7 0.7 5.1
M8
´
1.25 3 15 1.5 11
(bolt) M10
´
1.25 4 44 4.4 32
(nut) M6
´
1.0 2 10 1.0 7.2
M8
´
1.25 2 20 2.0 14
Cylinder head cover M6
´
1.0 2 10 1.0 7.2
Cylinder M6
´
1.0 1 10 1.0 7.2
Timing chain tensioner M6
´
1.0 2 10 1.0 7.2
Tensioner cap bolt M6
´
1.0 1 7 0.7 5.1
Timing chain guide (rear) M6
´
1.0 2 10 1.0 7.2
Decompression shaft M6
´
1.0 1 7 0.7 5.1
Decompression cable guide M6
´
1.0 1 10 1.0 7.2
Exhaust pipe (nut) M8
´
1.25 1 13 1.3 9.4
(bolt) M8
´
1.25 1 24 2.4 17
Silencer M8
´
1.25 2 35 3.5 25
Silencer clamp M8
´
1.25 1 20 2.0 14
Exhaust pipe protector M6
´
1.0 3 10 1.0 7.2
Spark arrester (for USA) M6
´
1.0 3 10 1.0 7.2
Silencer end pipe (for USA) M6
´
1.0 1 10 1.0 7.2
Clamp (air cleaner joint) M5
´
0.8 1 3 0.3 2.2
Clamp (carburetor joint) M4
´
0.7 1 3 0.3 2.2
Air filter joint clamp M6
´
1.0 1 3 0.3 2.2
Throttle cable cover M5
´
0.8 1 4 0.4 2.9
Air filter element M6
´
1.0 1 2 0.2 1.4
Air filter case cover M6
´
1.0 4 4 0.4 2.9
Radiator panel (upper) M6
´
1.0 2 10 1.0 7.2
Radiator M6
´
1.0 6 10 1.0 7.2
Radiator hose clamp M6
´
1.0 8 2 0.2 1.4
Impeller M8
´
1.25 1 14 1.4 10
Water pump housing cover M6
´ 1.0 3 10 1.0 7.2
Coolant drain bolt M6 ´ 1.0 1 10 1.0 7.2
Oil pump cover M5 ´ 0.8 1 4 0.4 2.9
Oil pump M6 ´ 1.0 3 10 1.0 7.2
Engine oil drain bolt (oil filter) M6 ´ 1.0 1 10 1.0 7.2
Oil filter cover M6 ´ 1.0 2 10 1.0 7.2
Oil delivery pipe 1 M10 ´ 1.25
M8 ´ 1.251
220
182.0
1.814
13
Oil hose clamp — 2 2 0.2 1.4
Clutch cover M6 ´ 1.0 7 10 1.0 7.2
Crankcase cover (right) M6 ´ 1.0 10 10 1.0 7.2
Crankcase cover (left) M6 ´ 1.0 8 10 1.0 7.2
Crankcase M6 ´ 1.0 12 12 1.2 8.7

2 - 18
SPECGENERAL SPECIFICATIONS (WR400F)
EC211000
GENERAL SPECIFICATIONS (WR400F)
Model name: WR400F (EUROPE)
WR400FN (AUS)
Model code number: 5GS9
Dimensions:
Overall length 2,171 mm (85.5 in)
Overall width 827 mm (32.6 in)
Overall height 1,303 mm (51.3 in)
Seat height 998 mm (39.3 in)
Wheelbase 1,490 mm (58.7 in)
Minimum ground clearance 373 mm (14.7 in)
Basic weight:
With oil and full fuel tank 121.5 kg (268 lb)
Engine:
Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 399 cm
3 (14.1 Imp oz, 13.5 US oz)
Bore ´ stroke 92.0 ´ 60.1 mm (3.62 ´ 2.37 in)
Compression ratio 12.5 : 1
Starting system Kick starter
Lubrication system: Dry sump
Oil type or grade:
Engine oil
API “SH” or higher grade
Oil capacity:
Engine oil
Periodic oil change 1.5 L (1.32 Imp qt, 1.59 US qt)
With oil filter replacement 1.6 L (1.41 Imp qt, 1.69 US qt)
Total amount 1.7 L (1.50 Imp qt, 1.80 US qt)
Coolant capacity (including all routes): 1.2 L (1.06 Imp qt, 1.27 US qt)
Air filter: Wet type element
-20
-4-10
140
3010
5020
6830
8640 50
104
122¡CTemp.
¡F
10W-30
10W-40
20W-40
20W-50
15W-40

2 - 24
SPECMAINTENANCE SPECIFICATIONS (WR400F)
Piston rings:
Top ring
Type Barrel ----
Dimensions (B ´ T) 1.2 ´ 3.5 mm (0.05 ´ 0.14 in) ----
End gap (installed) 0.20 ~ 0.35 mm
(0.008 ~ 0.014 in)0.6 mm
(0.024 in)
Side clearance (installed) 0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)0.12 mm
(0.005 in)
2nd ring
Type Taper ----
Dimensions (B ´ T) 1.00 ´ 3.35 mm (0.04 ´ 0.13 in) ----
End gap (installed) 0.40 ~ 0.55 mm
(0.016 ~ 0.022 in)0.9 mm
(0.035 in)
Side clearance 0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)0.12 mm
(0.005 in)
Oil ring
Dimensions (B ´ T) 2.0 ´ 2.9 mm (0.08 ´ 0.11 in) ----
End gap (installed) 0.2 ~ 0.5 mm (0.01 ~ 0.02 in) ----
Crankshaft:
Crank width “A” 61.95 ~ 62.00 mm
(2.439 ~ 2.441 in)----
Runout limit “C” 0.03 mm (0.0012 in) 0.05 mm
(0.002 in)
Big end side clearance “D” 0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)0.50 mm
(0.02 in)
Small end free play “F” 0.4 ~ 1.0 mm (0.02 ~ 0.04 in) 2.0 mm
(0.08 in)
Balancer:
Balancer drive method Gear ----
Decompression device:
Type Manual ----
Cable free play 5 ~ 9 mm (0.20 ~ 0.35 in)
Air filter oil grade: Engine oil ----Item Standard Limit
T
B
B
T
B
T

2 - 28
SPECMAINTENANCE SPECIFICATIONS (WR400F)
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M10S ´ 1.0 1 13 1.3 9.4
Camshaft cap M6 ´ 1.0 10 10 1.0 7.2
Cylinder head (stud bolt) M6 ´ 1.0 2 7 0.7 5.1
M8 ´ 1.25 3 15 1.5 11
(bolt) M10 ´ 1.25 4 44 4.4 32
(nut) M6 ´ 1.0 2 10 1.0 7.2
M8 ´ 1.25 2 20 2.0 14
Cylinder head cover M6 ´ 1.0 2 10 1.0 7.2
Cylinder M6 ´ 1.0 1 10 1.0 7.2
Timing chain tensioner M6 ´ 1.0 2 10 1.0 7.2
Tensioner cap bolt M6 ´ 1.0 1 7 0.7 5.1
Timing chain guide (rear) M6 ´ 1.0 2 10 1.0 7.2
Decompression shaft M6 ´ 1.0 1 7 0.7 5.1
Decompression cable guide M6 ´ 1.0 1 10 1.0 7.2
Exhaust pipe (nut) M8 ´ 1.25 1 13 1.3 9.4
(bolt) M8 ´ 1.25 1 24 2.4 17
Silencer M8 ´ 1.25 2 35 3.5 25
Silencer clamp M8 ´ 1.25 1 20 2.0 14
Exhaust pipe protector M6 ´ 1.0 3 10 1.0 7.2
Spark arrester (for USA) M6 ´ 1.0 3 10 1.0 7.2
Silencer end pipe (for USA) M6 ´ 1.0 1 10 1.0 7.2
Clamp (air cleaner joint) M5 ´ 0.8 1 3 0.3 2.2
Clamp (carburetor joint) M4 ´ 0.7 1 3 0.3 2.2
Air filter joint clamp M6 ´ 1.0 1 3 0.3 2.2
Throttle cable cover M5 ´ 0.8 1 4 0.4 2.9
Air filter element M6 ´ 1.0 1 2 0.2 1.4
Air filter case cover M6 ´ 1.0 4 4 0.4 2.9
Radiator panel (upper) M6 ´ 1.0 2 10 1.0 7.2
Radiator M6 ´ 1.0 6 10 1.0 7.2
Radiator hose clamp M6 ´ 1.0 8 2 0.2 1.4
Impeller M8 ´ 1.25 1 14 1.4 10
Water pump housing cover M6 ´ 1.0 3 10 1.0 7.2
Coolant drain bolt M6 ´ 1.0 1 10 1.0 7.2
Oil pump cover M5 ´ 0.8 1 4 0.4 2.9
Oil pump M6 ´ 1.0 3 10 1.0 7.2
Engine oil drain bolt (oil filter) M6 ´ 1.0 1 10 1.0 7.2
Oil filter cover M6 ´ 1.0 2 10 1.0 7.2
Oil delivery pipe 1 M10 ´ 1.25
M8 ´ 1.251
220
182.0
1.814
13
Oil hose clamp — 2 2 0.2 1.4
Clutch cover M6 ´ 1.0 7 10 1.0 7.2
Crankcase cover (right) M6 ´ 1.0 10 10 1.0 7.2
Crankcase cover (left) M6 ´ 1.0 8 10 1.0 7.2
Crankcase M6 ´ 1.0 12 12 1.2 8.7

2 - 38
SPEC

CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1
Hose guide
2
Brake hose
3
Regulator
4
Fuel tank breather hose
5
Oil tank breather hose
6
Clamp
7
“ENGINE STOP” button lead
8
Sub wire harness
9
Tail light lead
0
TPS (throttle position sensor) lead
A
Neutral switch lead
B
Oil hose
C
Cylinder head breather hose
D
CDI magneto lead
E
Hose holder
F
Clutch cable
G
Decompression cable
H
Lights switch lead
I
Carburetor breather hose
J
Overflow hose
K
Coolant reservoir tank breather hose

Pass the fuel tank breather
hose behind handlebar, then
insert it into the steering shaft
hole.
õ
Pass the decompression
cable, “ENGINE STOP” but-
ton lead and lights switch lead
under where the oil hose is
attached.
‚
Fasten the CDI magneto lead,
neutral switch lead “ENGINE
STOP” button lead and lights
switch lead to the frame with a
plastic locking tie.
ë
Pass the “ENGINE STOP” but-
ton lead and lights switch lead
along the inner side of the oil
tank breather hose.
ä
Fasten the sub wire harness,
“ENGINE STOP” button lead
and lights switch lead to the
frame in front of the protector
of the sub wire harness with a
plastic locking tie and cut off
the tie end.
ì
Pass the cylinder head
breather hose along the right
side of the oil tank breather
hose.
í
Fasten the sub wire harness
and “ENGINE STOP” button
lead to the frame with a plas-
tic locking tie and cut off the
tie end.
î
Pass the sub wire harness
between the engine brackets.

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
or
500 km
(300 mi)Every
fifth
or
1,000 km
(600 mi)
As re-
quiredRemarks
ENGINE OIL
Replace
cc
OIL FILTER
Clean
cc
VALVES
Check the valve clearances.
Inspect
Replace
cc
c
c
The engine must be cold.
Check the valve seats and
valve stems for wear.
VALVE SPRINGS
Inspect
Replace
c
c
Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
c
c
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
c
c
Inspect the camshaft sur-
face.
CAMSHAFT SPROCKETS
Inspect
Replace
c
c
Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
cc
c
c
Inspect crack
Remove carbon
PISTON RING
Inspect
Replace
c
cc
Check ring end gap
PISTON PIN
Inspect
Replace
c
c
CYLINDER HEAD
Inspect and clean
c
Remove carbon
Change gasket
CYLINDER
Inspect and clean
Replace
c
c
Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
cc
c
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
c
c


3

3 - 4
INSP
ADJ

PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator filler cap.
Check that the coolant level is correct in the coolant reservoir
tank.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-13
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-10
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-26 ~ 32
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-33 ~ 35
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-42 ~ 44
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-44 ~ 45
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-35 ~ 42
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks. —
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-46
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 22

3 - 7
INSP
ADJ
COOLANT REPLACEMENT
9. Fill:
lRadiator
lEngine
To specified level.
CAUTION:
lDo not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
lDo not use water containing impurities or oil.
Recommended coolant:
High quality ethylene glycol
anti-freeze containing
anti-corrosion for
aluminum engine
Coolant 1 and water
(soft water) 2 mixing ratio:
50%/50%
Coolant capacity:
1.2 L (1.06 Imp qt, 1.27 US qt)
Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
lWhen coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
lWhen coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
lWhen coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
10. Install:
lRadiator cap
11. Fill:
lCoolant reservoir tank
Midway a between maximum and min-
imum marks on the tank.
LOWFULLCOOLANTa

3 - 13
INSP
ADJ
1. Remove:
lSeat
2. Disconnect:
lTail light lead connectors 1
3. Remove:
lAir filter case cover 2
4. Remove:
lFitting bolt 1
lWasher 2
lAir filter element 3
lFilter guide 4
5. Clean:
lAir filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
lDo not twist the element when squeezing
the element.
lLeaving too much of solvent in the ele-
ment may result in poor starting.
6. Inspect:
lAir filter element
Damage ® Replace.
7. Apply:
lFoam-air-filter oil or engine mixing oil
To the element.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
8. Install:
lFilter guide 1
NOTE:
Align the projection a on filter guide with the
hole b in air filter element.
AIR FILTER CLEANING

3 - 14
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
9. Apply:
lLithium soap base grease
On the matching surface a on air filter
element.
10. Install:
lAir filter element 1
lWasher
lFitting bolt
NOTE:
Align the projection a on filter guide with the
hole b in air filter case.
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
ENGINE OIL LEVEL INSPECTION
1. Stand the motorcycle on a level surface.
NOTE:
lWhen checking the oil level make sure that
the motorcycle is upright.
lPlace the motorcycle on a suitable stand.
WARNING
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 minutes
while keeping the motorcycle upright.
Then stop the engine and inspect the oil
level.
3. Remove:
lOil tank cap 1