light YAMAHA WR 400F 2001 Owner's Guide

4 - 27
ENGCAMSHAFTS
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.
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 bolts (camshaft cap) 5 in a
crisscross pattern.
CAUTION:
The bolts (camshaft cap) must be tight-
ened evenly or damage to the cylinder
head, camshaft caps and camshaft will
result.
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
tensioner UP mark a facing upward,
install the gasket 1 and the chain ten-
sioner 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..
Tensioner cap bolt:
7 Nm (0.7 m • kg, 5.1 ft • lb)

4 - 37
ENGVALVES AND VALVE SPRINGS
9. Lap:
lValve face
lValve seat
NOTE:
After refacing the valve seat or replacing the
valve and valve guide, the valve seat and
valve face should be lapped.
Lapping steps:
lApply a coarse lapping compound to the
valve face.
CAUTION:
Do not let the compound enter the gap
between the valve stem and the guide.
lApply molybdenum disulfide oil to the
valve stem.
lInstall the valve into the cylinder head.
lTurn the valve until the valve face and
valve seat are evenly polished, then clean
off all of the compound.
NOTE:
For best lapping results, lightly tap the valve
seat while rotating the valve back and forth
between your hands.
lApply a fine lapping compound to the
valve face and repeat the above steps.
NOTE:
After every lapping operation be sure to
clean off all of the compound from the valve
face and valve seat.
lApply Mechanic’s blueing dye (Dykem) to
the valve face.
lInstall the valve into the cylinder head.
lPress the valve through the valve guide
and onto the valve seat to make a clear
pattern.
lMeasure the valve seat width again. If the
valve seat width is out of specification,
reface and relap the valve seat.

4 - 39
ENGVALVES AND VALVE SPRINGS
Combination of cylinder head and valve
lifter
1. Combination:
For this combination, match the paint
color on the cylinder head with that on
the valve lifter according to the chart
below.
NOTE:
When you purchase a cylinder head, you can-
not designate its size. Choose the valve lifter
that matches the above chart.Combination
Cylinder head mark
a (color)Valve lifter mark
b (color)
Blue Blue
Yellow Yellow
Purple Black
ab
ASSEMBLY AND INSTALLATION
1. Apply:
lMolybdenum disulfide oil
Onto the valve stem and valve stem
seal.
2. Install:
lValves 1
lValve spring seats 2
lValve stem seals 3
lValve springs 4
lValve spring retainers 5
NOTE:
lMake sure that each valve is installed in its
original place, also referring to the painted
color as follows.
Intake (middle) a: light blue
Intake (right/left) b: white
Exhaust: not paint
lInstall the valve springs with the larger pitch
c facing upward.
dSmaller pitch
New

4 - 40
ENG
3. Install:
lValve cotters
NOTE:
While compressing the valve spring with a
valve spring compressor 1 install the valve
cotters.
4. To secure the valve cotters onto the
valve stem, lightly tap the valve tip with a
piece of wood.
CAUTION:
Hitting the valve tip with excessive force
could damage the valve.
Valve spring compressor:
YM-04019/90890-04019
5. Install:
lAdjusting pad 1
lValve lifter 2
NOTE:
lApply the engine oil on the valve lifters.
lApply the molybdenum disulfide oil on the
valve stem end.
lValve lifter must turn smoothly when rotated
with a finger.
lBe careful to reinstall valve lifters and pads
in their original place.
VALVES AND VALVE SPRINGS

4 - 95
ENGCRANKCASE AND CRANKSHAFT
REMOVAL POINTS
Crankcase
1. Separate:
lCrankcase (right)
lCrankcase (left)
Separation steps:
lRemove the crankcase bolts, hose guide
and clutch cable holder.
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove
them.
lRemove the crankcase (right).
NOTE:
lPlace the crankcase with its left side
downward and split it by inserting a screw-
driver tip into the splitting slit a in the
crankcase.
lLift the crankcase (right) horizontally while
lightly patting the case splitting slit and
engine mounting boss using a soft ham-
mer, and leave the crankshaft and trans-
mission with the crankcase (left).
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case.
Do not tap on gasket mating surface.
Work slowly and carefully. Make sure the
case halves separate evenly. If one end
“hangs up”, take pressure off the push
screw, realign, and start over. If the
cases do not separate, check for a
remaining case screw or fitting. Do not
force.
lRemove the dowel pins and O-ring.
a

4 - 99
ENGCRANKCASE AND CRANKSHAFT
2. Check:
lShifter operation
lTransmission operation
Unsmooth operation ® Repair.
3. Install:
lOil strainer 1
lBolt (oil strainer) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
4. Apply:
lSealant
On the crankcase (right) 1.
NOTE:
Clean the contacting surface of crankcase (left
and right) before applying the sealant.
5. Install:
lDowel pin 1
lO-ring 2
lCrankcase (right)
To crankcase (left).
NOTE:
lFit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft ham-
mer.
lWhen installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
Quick gasket®:
ACC-QUICK-GS-KT
YAMAHA Bond No. 1215:
90890-85505
New

4 - 102
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H3000
REMOVAL POINTS
Shift fork, shaft cam and transmission
1. Remove:
lShift forks
lShift cam
lMain axle
lDrive axle
NOTE:
lTap lightly on the transmission drive axle and
shift cam with a soft hammer to remove.
lRemove assembly carefully. Note the posi-
tion of each part. Pay particular attention to
the location and direction of shift forks.
EC4H4000
INSPECTION
EC4H4200
Gears
1. Inspect:
lMatching dog a
lGear teeth b
lShift fork groove c
Wear/damage ® Replace.
2. Inspect:
lO-ring 1
Damage ® Replace.
3. Check:
lGears movement
Unsmooth movement ® Repair or
replace.
EC4H4600
Bearing
1. Inspect:
lBearing 1
Rotate inner race with a finger.
Rough spot/seizure ® Replace.

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
lCopper washer 1
lUnion bolt 2
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the caliper.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
3. Install:
lBrake hose holder 1
lCaliper 2
lBolt (caliper) 3
NOTE:
Fit the brake hose holder cut a over the pro-
jection b on the front fork and clamp the brake
hose.
4. Tighten:
lPad pin 4
5. Install:
lPad pin plug 5
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
EC5A5100
Rear caliper
1. Install:
lPad support 1
lBrake pad 2
lPad pin 3
NOTE:
lInstall the brake pads with their projections
a into the caliper recesses b.
lTemporarily tighten the pad pin at this point.

5 - 25
CHASFRONT BRAKE AND REAR BRAKE
4. Install:
lCopper washer 1
lBrake hose 2
lUnion bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the master cylinder.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
EC5A5500
Rear brake hose
1. Install:
lCopper washer 1
lBrake hose 2
lCopper washer 3
lUnion bolt 4
WARNING
Always use new copper washers.
CAUTION:
When installing the brake hose, first align
the tooth a on the copper washer 1 with
the projection b on the master cylinder.
Then, align the pipe portion c on the end
of the brake hose with the tooth d on the
copper washer 1 and tighten the union
bolt.
New
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 28
CHASFRONT FORK
EC550000
FRONT FORK
Extent of removal:1 Front fork removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT FORK REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Front caliper Refer to “FRONT BRAKE AND REAR
BRAKE” section.
Headlight
Handlebar Refer to “HANDLEBAR” section.
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
1