Yamaha YFM400FWA 2000 5GH3-AE1 User manual

SERVICEMANUAL
YFM400FWA(M)5GH3-AE1
2000

YFM400FWA(M) 2000
SERVICE MANUAL
 1999 by Yamaha Motor Co., Ltd.
First Edition, July 1999
All rights reserved. Any reproduction or
unauthorized use without the written
permission of Yamaha Motor Co., Ltd.
is expressly prohibited.

EB001000
NOTICE
This manual was produced by the Yamaha Motor Company primarily for use by Yamaha
dealers and their qualified mechanics. It is not possible to include all the knowledge of a
mechanic in one manual, so it is assumed that anyone who uses this book to perform mainte-
nance and repairs on Yamaha machine has a basic understanding of the mechanical ideas
and the procedures of machine repair. Repairs attempted by anyone without this knowledge
are likely to render the machine unsafe and unfit for use.
Yamaha Motor Company, Ltd. is continually striving to improve all its models. Modifications
and significant changes in specifications or procedures will be forwarded to all authorized
Yamaha dealers and will appear in future editions of this manual where applicable.
N
OTE:
Designs and specifications are subject to change without notice.
IMPORTANT INFORMATION
Particularly important information is distinguished in this manual by the following notations.
The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED!
Failure to follow WARNING instructions could result in severe injury or
death to the machine operator, a bystander or a person inspecting or
repairing the machine.
A CAUTION indicates special precautions that must be taken to avoid
damage to the machine.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
NOTE:

EB002000
HOW TO USE THIS MANUAL
MANUAL ORGANIZATION
This manual consists of chapters for the main categories of subjects. (See “Illustrated sym-
bols”)
1st title 1 : This is the title of the chapter with its symbol in the upper right corner of each
page.
2nd title 2 : This title indicates the section of the chapter and only appears on the first page of
each section. It is located in the upper left corner of the page.
3rd title 3 : This title indicates a sub-section that is followed by step-by-step procedures
accompanied by corresponding illustrations.
EXPLODED DIAGRAMS
To help identify parts and clarify procedure steps, there are exploded diagrams at the start of
each removal and disassembly section.
1. An easy-to-see exploded diagram 4 is provided for removal and disassembly jobs.
2. Numbers 5 are given in the order of the jobs in the exploded diagram. A number that is
enclosed by a circle indicates a disassembly step.
3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol
marks 6 . The meanings of the symbol marks are given on the next page.
4. A job instruction chart 7 accompanies the exploded diagram, providing the order of jobs,
names of parts, notes in jobs, etc.
5. For jobs requiring more information, the step-by-step format supplements 8 are given in
addition to the exploded diagram and the job instruction chart.

EB003000
ILLUSTRATED SYMBOLS
Illustrated symbols 1 to 0 are printed on
the top right of each page and indicate the
subject of each chapter.
1 General information
2 Specifications
3 Periodic inspections and adjustments
4 Engine
5 Cooling system
6 Carburetion
7 Drive train
8 Chassis
9 Electrical
0 Troubleshooting
Illustrated symbols A to H are used to
identify the specifications appearing in the
text.
A Can be serviced with engine mounted
B Filling fluid
C Lubricant
D Special tool
E Torque
F Wear limit, clearance
G Engine speed
H
Ω
, V, A
Illustrated symbols I to N in the exploded
diagrams indicate the types of lubricants
and lubrication points.
I Apply engine oil
J Apply gear oil
K Apply molybdenum disulfide oil
L Apply wheel bearing grease
M Apply lightweight lithium-soap base grease
N Apply molybdenum disulfide grease
Illustrated symbols Oto Pin the exploded
diagrams indicate where to apply a locking
agent Oand when to install a new part P.
OApply the locking agent (LOCTITE)
PReplace
12
34
56
78
90
AB
CD
EF
GH
IJK
LMN
OP
GEN
INFO SPEC
INSP
ADJ ENG
COOL CARB
DRIV
CHAS
–+
ELEC TRBL
SHTG
T
R
.
.
GM
E
BLS M
LT New

TABLE OF CONTENTS
GENERAL INFORMATION
1
SPECIFICATIONS
SPEC
2
PERIODIC INSPECTION AND
ADJUSTMENTS
3
ENGINE
ENG
4
COOLING SYSTEM
COOL
5
CARBURETION
CARB
6
DRIVE TRAIN
DRIV
7
CHASSIS
CHAS
8
ELECTRICAL
ELEC
9
TROUBLESHOOTING
10
GEN
INFO
INSP
ADJ
–+
TRBL
SHTG

GEN
INFO
1

GEN
INFO
CHAPTER 1.
GENERAL INFORMATION
MACHINE IDENTIFICATION .........................................................................1-1
VEHICLE IDENTIFICATION NUMBER ..................................................1-1
MODEL LABEL ......................................................................................1-1
FEATURES ....................................................................................................1-2
LIQUID COOLING ENGINE ...................................................................1-2
PARK POSITION ...................................................................................1-2
IMPORTANT INFORMATION .......................................................................1-3
PREPARATION FOR REMOVAL PROCEDURES .................................1-3
REPLACEMENT PARTS ........................................................................1-3
GASKETS, OIL SEALS AND O-RINGS ................................................1-3
LOCK WASHERS/PLATES AND COTTER PINS ..................................1-4
BEARINGS AND OIL SEALS ................................................................1-4
CIRCLIPS ...............................................................................................1-4
CHECKING OF CONNECTIONS ...................................................................1-5
SPECIAL TOOLS ...........................................................................................1-6

GEN
INFO

1 - 1
GEN
INFO
MACHINE IDENTIFICATION
GENERAL INFORMATION
MACHINE IDENTIFICATION
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1 is
stamped into the left side of the frame.
MODEL LABEL
The model label 1 is affixed to the frame.
This information will be needed to order
spare parts.

1 - 2
GEN
INFO
FEATURES
LIQUID COOLING ENGINE
Compact liquid cooled 45˚ inclined engine.
A liquid cooling system has been incorpo-
rated for stable power and engine endur-
ance.
1 Radiator
2 Thermo switch
3 Fan motor
PARK POSITION
When the drive select lever is shifted into
the park position, a stopper lever is
engaged into the stopper gear preventing
the drive select lever and transmission from
moving.
When the drive select lever is at the “L”,
“H”, “N”, or “R” positions, the stopper
lever end 1 is moved away from the stop-
per gear 2 by the return spring 3 .
When the drive select lever is in the “P”
position, the lever cam 4 at the side of the
shift cam 5 lifts the stopper lever end 6
and the stopper lever end locks the drive
axle 7 .
When the stopper lever end 1 is not syn-
chronized, a torsion spring 8 retains the
rotation force of the shift cam 5 until it is
synchronized.
FEATURES

1 - 3
GEN
INFO
EB101000
IMPORTANT INFORMATION
PREPARATION FOR REMOVAL
PROCEDURES
1.Remove all dirt, mud, dust and foreign
material before removal and disassembly.
2.Use proper tools and cleaning equipment.
Refer to the “SPECIAL TOOLS” section.
3.When disassembling the machine, always
keep mated parts together. This includes
gears, cylinder, piston and other parts that
have been “mated” through normal wear.
Mated parts must always be reused or
replaced as an assembly.
4.During machine disassembly, clean all
parts and place them in trays in the order
of disassembly. This will speed up assem-
bly and allow for the correct installation of
all parts.
5.Keep all parts away from any source of
fire.
EB101010
REPLACEMENT PARTS
1.Use only genuine Yamaha parts for all
replacements. Use oil and grease recom-
mended by Yamaha for all lubrication
jobs. Other brands may be similar in func-
tion and appearance, but inferior in qual-
ity.
EB101020
GASKETS, OIL SEALS AND O-RINGS
1.Replace all gaskets, seals and O-rings
when overhauling the engine. All gasket
surfaces, oil seal lips and O-rings must be
cleaned.
2.Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.
IMPORTANT INFORMATION

GEN
INFO
1 - 4
EB101030
LOCK WASHERS/PLATES AND COTTER
PINS
1.Replace all lock washers/plates 1 and cot-
ter pins after removal. Bend lock tabs
along the bolt or nut flats after the bolt or
nut has been tightened to specification.
EB101040
BEARINGS AND OIL SEALS
1.Install bearings and oil seals so that the
manufacturer’s marks or numbers are vis-
ible. When installing oil seals, apply a
light coating of lightweight lithium base
grease to the seal lips. Oil bearings liber-
ally when installing, if appropriate.
1 Oil seal
CAUTION:
Do not use compressed air to spin the bear-
ings dry. This will damage the bearing sur-
faces.
1 Bearing
EB101050
CIRCLIPS
1.Check all circlips carefully before reas-
sembly. Always replace piston pin clips
after one use. Replace distorted circlips.
When installing a circlip 1 , make sure
that the sharp-edged corner 2 is posi-
tioned opposite the thrust 3 it receives.
See sectional view.
4 Shaft
IMPORTANT INFORMATION

1 - 5
GEN
INFO
CHECKING OF CONNECTIONS
EB801000
CHECKING OF CONNECTIONS
Check the connectors for stains, rust, mois-
ture, etc.
1.Disconnect:
●
Connector
2.Check:
●
Connector
Moisture → Dry each terminal with an air
blower.
Stains/rust → Connect and disconnect the
terminals several times.
3.Check:
●
Connector leads
Looseness → Bend up the pin 1 and con-
nect the terminals.
4.Connect:
●
Connector terminals
N
OTE:
The two terminals “click” together.
5.Check:
●
Continuity (using a pocket tester)
N
OTE:
●
If there is no continuity, clean the termi-
nals.
●
When checking the wire harness be sure
to perform steps 1 to 3.
● As a quick remedy, use a contact revital-
izer available at most part stores.
●
Check the connector with a pocket tester
as shown.

GEN
INFO
1 - 6
SPECIAL TOOLS
EB102001
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly.
Use only the appropriate special tools; this will help prevent damage caused by the use of
inappropriate tools or improvised techniques. Special tools may differ by shape and part
number from country to country. In such a case, two types are provided.
When placing an order, refer to the list provided below to avoid any mistakes.
For US and CDN
P/N. YM-, YU-, YS-, YK-, ACC-
Except for US and CDN
P/N. 90890-
Tool No. Tool name/How to use Illustration
Bolt
90890-01083
Weight
90890-01084
Set
YU-01083-A
Slide hammer bolt (M6)/weight/set
These tools are used to remove the
rocker arm shaft.
90890-01135
YU-01135-A
Crankcase separating tool
This tool is used to separate the crank-
case.
90890-01225
YM-01225-A
Valve guide remover (7.0 mm)
This tool is needed to remove and
install the valve guide.
90890-04017
YM-04017
Valve guide installer (7.0 mm)
This tool is needed to install the valve
guide.
90890-01227
YM-01227
Valve guide reamer (7.0 mm)
This tool is needed to rebore the new
valve guide.
90890-01231
YM-01231
Gear lash measurement tool
This tool is used to measure the gear
lash.
90890-01235
YU-01235
Rotor holding tool
This tool is needed to hold the starter
puller when removing/installing the
starter puller bolt or camshaft sprocket
bolts.

GEN
INFO
1 - 7
SPECIAL TOOLS
Kit
90890-04088
Bolt
90890-01275
Buffer boss installer set
Crankshaft installer bolt
These tools are used to install the
crankshaft.
YU-90050
Crankshaft installer set
These tools are used to install the
crankshaft.
Adapter
YM-33279
Spacer
90890-04060
YM-90070-A
Adapter (#11)
Spacer (crankshaft installer)
These tools are used to install the
crankshaft.
90890-01304
YU-01304
Piston pin puller
This tool is used to remove the piston
pin.
90890-01311
YU-08035
Tappet adjusting tool (3 mm)
This tool is necessary for adjusting the
valve clearance.
90890-01312
YM-01312-A
Fuel level gauge
This gauge is used to measure the fuel
level in the float chamber.
90890-01325
YU-24460-01
Radiator cap tester
This tool is used to check the cooling
system.
90890-01352
YU-33984
Adapter
This tool is used to check the cooling
system.
90890-01348
Locknut wrench
This tool is needed when removing or
installing the secondary sheave
spring.
Tool No. Tool name/How to use Illustration

GEN
INFO
1 - 8
SPECIAL TOOLS
90890-04134
YM-04134
Sheave spring compressor
This tool is needed when removing or
installing the secondary sheave
spring.
90890-04135
YM-04135
Sheave fixed block
This tool is needed when removing or
installing the secondary sheave
spring.
90890-01404
YM-01404
Flywheel puller
These tools are needed to remove the
rotor.
90890-01327
YM-01327
Damper rod holder (30 mm)
This tool is needed to loosen and
tighten the steering stem bearing
retainer.
90890-01426
YU-38411
Oil filter wrench
This tool is needed to loosen or tighten
the oil filter cartridge.
90890-01430
YM-38404
Ring nut wrench
This tool is needed to removing and
installing the middle driven shaft bear-
ing retainer.
90890-01467
YM-01467
90890-01475
YM-01475
Gear lash measurement tool
This tool is used to measure the gear
lash.
90890-01701
YU-01880
Sheave holder
This tool is needed to hold the primary
sheave when removing or installing
the sheave bolts.
Set
90890-03081
YU-33223
Adapter
90890-04082
YU-33223-3
Compression gauge set
Adapter
These tools are needed to measure
engine compression.
Tool No. Tool name/How to use Illustration

GEN
INFO
1 - 9
SPECIAL TOOLS
90890-03112
YU-03112
Pocket tester
This instrument is needed for checking
the electrical system.
90890-03113
Engine tachometer
This tool is needed for observing
engine rpm.
YU-8036-A
Inductive tachometer
This tool is needed for observing
engine rpm.
90890-03141
YM-33277-A
Timing light
This tool is necessary for checking
ignition timing.
90890-04019
YM-04019
Valve spring compressor
This tool is needed to remove and
install the valve assemblies.
Middle driven shaft
bearing driver
90890-04058
YM-04058-1
Mechanical seal
installer
90890-04078
YM-33221
Middle driven shaft bearing driver
Mechanical seal installer
These tools are used to install the
water pump seal.
90890-04050
YM-04050
Bearing retainer wrench
This tool is needed when removing or
installing the final drive shaft bearing
retainer.
90890-04062
YM-04062
Universal joint holder
This tool is needed when removing or
installing the universal joint yoke nut.
90890-04086
YM-91042
Clutch holding tool
This tool is needed to hold the clutch
carrier when removing or installing the
carrier nut.
Tool No. Tool name/How to use Illustration

GEN
INFO
1 - 10
SPECIAL TOOLS
90890-04128
YM-04128
Bearing retainer wrench
This tool is needed when removing or
installing the middle driven pinion
gear bearing retainer.
90890-04129
YM-04129
Pinion gear fix clamp
This tool is used to hold the shift cam.
90890-06754
Ignition checker
This instrument is necessary for check-
ing the ignition system components.
YM-34487
Dynamic spark tester
This instrument is necessary for check-
ing the ignition system components.
Bond
90890-85505
Sealant
ACC-11001-05-01
Yamaha bond No. 1215
Sealant (Quick Gasket®)
This sealant (bond) is used on crank-
case mating surfaces, etc.
Tool No. Tool name/How to use Illustration

SPEC
2