2000 YAMAHA WR 400F light

3 - 46
INSP
ADJ
ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
lSpark plug
2. Inspect:
lElectrode 1
Wear/damage ® Replace.
lInsulator color 2
Normal condition is a medium to light
tan color.
Distinctly different color ® Check the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
lPlug gap a
Use a wire gauge or thickness gauge.
Out of specification ® Re-gap.
4. Clean the plug with a spark plug cleaner
if necessary.
Spark plug gap:
0.7 ~ 0.8 mm (0.028 ~ 0.031 in)
Standard spark plug:
CR8E (NGK)
U24ESR-N (DENSO)
5. Tighten:
lSpark plug
NOTE:
lBefore installing a spark plug, clean the gas-
ket surface and plug surface.
lFinger-tighten a the spark plug before torqu-
ing to specification b.
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)

3 - 47
INSP
ADJ
IGNITION TIMING CHECK
IGNITION TIMING CHECK
1. Remove:
lTiming plug 1
2. Attach:
lTiming light
lInductive tachometer
To the spark plug lead.
3. Check:
lIgnition timing
Timing light:
YM-33277-A/90890-03141
Inductive tachometer
YU-8036-1
Engine tachometer:
90890-03113
Checking steps:
lStart the engine and let it warm up. Let the
engine run at the specified speed.
Engine speed:
1,700 ~ 1,900 r/min
lVisually check the stationary pointer a is
within the firing range b on the rotor.
Incorrect firing range ® Check rotor and
pickup assembly.
4. Install:
lTiming plug

3 - 48
INSP
ADJ
REPLACING THE HEADLIGHT BULBS
REPLACING THE HEADLIGHT BULBS
The following procedure applies to both of the
headlight bulb.
1. Remove:
lNumber plate
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
2. Remove:
lHeadlight bulb holder cover 1
3. Detach:
lHeadlight bulb holder 1
4. Remove:
lHeadlight bulb 2
WARNING
Since the headlight bulb gets extremely
hot, keep flammable products and your
hands away from the bulb unit it has cooled
down.
5. Install:
lHeadlight bulb
Secure the new headlight bulb with the
headlight bulb holder.
CAUTION:
Avoid touching the glass part of the head-
light bulb to keep it free form oil, otherwise
the transparency of the glass, the life of the
bulb and the luminous flux will be
adversely affected. If the headlight bulb
gets soiled, thoroughly clean it with a cloth
moistened with alcohol or lacquer thinner.
6. Attach:
lHeadlight bulb holder
7. Install:
lHeadlight bulb holder cover
8. Install:
lNumber plate
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
New

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INSP
ADJ
ADJUSTING THE HEADLIGHT BEAMS
ADJUSTING THE HEADLIGHT BEAMS
The following procedure applies to both of the
headlight.
1. Adjust:
lHeadlight beam (vertically)
Adjusting steps:
lTurn the adjusting screw 1 in direction a
or b.
Direction a Headlight beam is raised.
Direction b Headlight beam is lowered.

ENG

4 - 1
3EC400000
ENGINE
EC4R0000
SEAT, FUEL TANK AND SIDE COVERS
SEAT, FUEL TANK AND SIDE COVERS

For USA, CDN
õ
Except for USA, CDN
Extent of removal:
1
Seat removal
2
Fuel tank removal
3
Side covers removal
4
Number plate removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
SEAT, FUEL TANK AND SIDE
COVERS REMOVAL
Turn the fuel cock to “OFF”.
Disconnect the fuel hose.
1 Seat 1
2 Air scoop (left and right) 2
3 Fitting band 1 Remove on fuel tank side.
4 Bolt (fuel tank) 2
5 Fuel tank 1
6 Side cover (left) 1
7 Side cover (right) 1
8 Headlight coupler 1
9 Number plate 1
13
4
2
3

4

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ENGCARBURETOR
10. Install:
lStarter jet 1
lPilot jet 2
lSpacer 3
lNeedle jet 4
lMain jet 5
11. Install:
lValve seat
lScrew (valve seat) 1
lNeedle valve 2
lFloat 3
lFloat pin 4
NOTE:
lAfter installing the needle valve to the float,
install them to the carburetor.
lCheck the float for smooth movement.
12. Install:
lPilot screw 1
lSpring 2
lWasher 3
lO-ring 4
* Except for USANote the following installation points:
lTurn in the pilot screw until it is lightly
seated.
lTurn out the pilot screw by the number of
turns recorded before removing.
Pilot screw:
1-5/8 turns out
*1-1/2 turns out
(for reference only)
13. Install:
lFloat chamber 1
lScrew (float chamber) 2
lCable holder (throttle stop screw cable)
3
lHose holder (carburetor breather hose)
4

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ENGCAMSHAFTS
Timing chain tensioner
1. Check:
lWhile pressing the tensioner rod lightly
with fingers, use a thin screwdriver 1
and wind the tensioner rod up fully
clockwise.
lWhen releasing the screwdriver by
pressing lightly with fingers, make sure
that the tensioner rod will come out
smoothly.
lIf not, replace the tensioner assembly.
ASSEMBLY AND INSTALLATION
1. Install:
lExhaust camshaft 1
lIntake camshaft 2
Installation steps:
lTurn the crankshaft counterclockwise until
the “I” mark a on the rotor is aligned with
the stationary pointer b on the crankcase
cover.
lFit the timing chain 3 onto both camshaft
sprockets and install the camshafts on the
cylinder head.
NOTE:
The camshafts should be installed onto the
cylinder head so that the exhaust cam
sprocket punch mark c and the intake cam
sprocket punch mark d align with the sur-
face of the cylinder head.
CAUTION:
Do not turn the crankshaft during the
camshaft installation. Damage or
improper valve timing will result.

4 - 26
ENGCAMSHAFTS
lInstall the dowel pins, clips and camshaft
caps 4.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
.
NOTE:
Tighten the camshaft cap bolts 5 in a criss-
cross pattern.
CAUTION:
The Bolts (camshaft cap) must be tightened
evenly or damage to the cylinder head,
camshaft caps and camshaft will result.
2. Install:
lTiming chain tensioner
3. Turn:
lCrankshaft
Counterclockwise several turns.
4. Check:
lRotor “I” mark
Align with the crankcase stationary
pointer.
lCamshaft match marks
Align with the cylinder head surface.
Out of alignment ® Adjust. Installation steps:
lWhile pressing the tensioner rod lightly with
fingers, use a thin screwdriver and wind the
tensioner rod up fully clockwise.
lWith the rod fully wound and the chain ten-
sioner UP mark a facing upward, install the
gasket 1 and the chain tensioner 2, and
tighten the bolt 3 to the specified torque.
T R..
Bolt (timing chain tensioner):
10 Nm (1.0 m • kg, 7.2 ft • lb)
lRelease the screwdriver, check the ten-
sioner rod to come out and tighten the
gasket 4 and the cap bolt 5 to the speci-
fied torque.
T R..
Cap bolt (timing chain tensioner):
7 Nm (0.7 m • kg, 5.1 ft • lb)