Yamaha YP400T User manual

LIT-11616-18-38 5RU-28197-10
YP400T
SERVICE MANUAL

EAS00001
YP400T
SERVICE MANUAL
©2004 by Yamaha Motor Corporation, U.S.A.
First edition, June 2004
All rights reserved.
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Corporation, U.S.A.
is expressly prohibited.
Printed in U.S.A.
P/N LIT-11616-18-38

EAS00003
NOTICE
This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha deal-
ers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in
one manual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha
vehicles should have a basic understanding of mechanics and the techniques to repair these types
of vehicles. Repair and maintenance work attempted by anyone without this knowledge is likely to
render the vehicle unsafe and unfit for use.
This model has been designed and manufactured to perform within certain specifications in regard
to performance and emissions. Proper service with the correct tools is necessary to ensure that the
vehicle will operate as designed. If there is any question about a service procedure, it is imperative
that you contact a Yamaha dealer for any service information changes that apply to this model. This
policy is intended to provide the customer with the most satisfaction from his vehicle and to conform
to federal environmental quality objectives.
Yamaha Motor Company, Ltd. is continually striving to improve all of its models. Modifications and
significant changes in specifications or procedures will be forwarded to all authorized Yamaha deal-
ers and will appear in future editions of this manual where applicable.
NOTE:
_
• This Service Manual contains information regarding periodic maintenance to the emission control
system. Please read this material carefully.
• Designs and specifications are subject to change without notice.
EAS00005
IMPORTANT MANUAL INFORMATION
Particularly important information is distinguished in this manual by the following.
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 scooter operator, a bystander or a person checking or repairing the scooter.
A CAUTION indicates special precautions that must be taken to avoid damage
to the scooter.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
NOTE:

EAS00007
HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive
explanations of all installation, removal, disassembly, assembly, repair and check procedures are
laid out with the individual steps in sequential order.
1The manual is divided into chapters. An abbreviation and symbol in the upper right corner of
each page indicate the current chapter.
Refer to “SYMBOLS”.
2Each chapter is divided into sections. The current section title is shown at the top of each page,
except in Chapter 3 (“PERIODIC CHECKS AND ADJUSTMENTS”), where the sub-section
title(s) appears.
3Sub-section titles appear in smaller print than the section title.
4To help identify parts and clarify procedure steps, there are exploded diagrams at the start of
each removal and disassembly section.
5Numbers are given in the order of the jobs in the exploded diagram. A circled number indicates a
disassembly step.
6Symbols indicate parts to be lubricated or replaced.
Refer to “SYMBOLS”.
7A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
8Jobs requiring more information (such as special tools and technical data) are described sequen-
tially.

EAS00008
SYMBOLS
The following symbols are not relevant to
every vehicle.
Symbols 1to 9indicate the subject of each
chapter.
1General information
2Specifications
3Periodic checks and adjustments
4Chassis
5Engine
6Cooling system
7Fuel injection system
8Electrical system
9Troubleshooting
Symbols 0to Gindicate the following.
0Serviceable with engine mounted
AFilling fluid
BLubricant
CSpecial tool
DTightening torque
EWear limit, clearance
FEngine speed
GElectrical data
Symbols Hto Min the exploded diagrams
indicate the types of lubricants and lubrication
points.
HEngine oil
IGear oil
JMolybdenum-disulfide oil
KWheel-bearing grease
LLithium-soap-based grease
MMolybdenum-disulfide grease
Symbols Nto Oin the exploded diagrams
indicate the following.
NApply locking agent (LOCTITE®)
OReplace the part
12
34
56
78
90
AB
CD
EFG
HIJ
KLM
NO
GEN
INFO
SPEC
CHK
ADJ
CHAS
ENG
COOL
FI –+
ELEC
TRBL
SHTG
T
R
.
.
EGM
BLS M
LT
New

EAS00010
TABLE OF CONTENTS
GENERAL INFORMATION GEN
INFO 1
SPECIFICATIONS SPEC 2
PERIODIC CHECKS AND
ADJUSTMENTS CHK
ADJ 3
CHASSIS CHAS 4
ENGINE ENG 5
COOLING SYSTEM COOL 6
FUEL INJECTION SYSTEM FI 7
ELECTRICAL SYSTEM ELEC 8
TROUBLESHOOTING TRBL
SHTG 9
–+

CONTENTS
CHAPTER 1
GENERAL INFORMATION
SCOOTER IDENTIFICATION..........................................................................1-1
VEHICLE IDENTIFICATION NUMBER .....................................................1-1
MODEL LABEL..........................................................................................1-1
FEATURES......................................................................................................1-2
OUTLINE OF THE FI SYSTEM.................................................................1-2
FI SYSTEM................................................................................................1-3
INSTRUMENT FUNCTIONS .....................................................................1-4
IMPORTANT INFORMATION .......................................................................1-10
PREPARATION FOR REMOVAL AND DISASSEMBLY......................... 1-10
REPLACEMENT PARTS.........................................................................1-10
GASKETS, OIL SEALS AND O-RINGS ..................................................1-10
LOCK WASHERS/PLATES AND COTTER PINS ...................................1-11
BEARINGS AND OIL SEALS ..................................................................1-11
CIRCLIPS ................................................................................................1-11
CHECKING THE CONNECTIONS ................................................................1-12
SPECIAL TOOLS ..........................................................................................1-13
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS ........................................................................2-1
ENGINE SPECIFICATIONS ...........................................................................2-2
CHASSIS SPECIFICATIONS ........................................................................2-10
ELECTRICAL SPECIFICATIONS .................................................................2-14
CONVERSION TABLE ..................................................................................2-17
GENERAL TIGHTENING TORQUE SPECIFICATIONS...............................2-17

TIGHTENING TORQUES ..............................................................................2-18
ENGINE TIGHTENING TORQUES.........................................................2-18
CHASSIS TIGHTENING TORQUES.......................................................2-21
LUBRICATION POINTS AND LUBRICANT TYPES ....................................2-23
ENGINE LUBRICATION POINTS AND LUBRICANT TYPES ................2-23
CHASSIS LUBRICATION POINTS AND LUBRICANT TYPES .............2-25
COOLING SYSTEM DIAGRAMS ..................................................................2-26
CABLE ROUTING .........................................................................................2-28
CHAPTER 3
PERIODIC CHECKS AND ADJUSTMENTS
INTRODUCTION..............................................................................................3-1
PERIODIC MAINTENANCE CHART FOR THE EMISSION
CONTROL SYSTEM........................................................................................3-1
GENERAL MAINTENANCE AND LUBRICATION CHART............................3-2
COWLING AND COVERS...............................................................................3-4
PASSENGER SEAT AND SIDE COVERS................................................3-4
RIDER SEAT AND STORAGE BOX .........................................................3-5
SIDE COVER MOULDINGS AND FOOTREST BOARDS ........................3-7
FRONT COWLING ....................................................................................3-8
AIR FILTER CASES ......................................................................................3-10

ENGINE .........................................................................................................3-11
ADJUSTING THE VALVE CLEARANCE ................................................3-11
ADJUSTING THE EXHAUST GAS VOLUME .........................................3-16
CHECKING THE ENGINE IDLING SPEED ............................................3-17
ADJUSTING THE THROTTLE CABLE FREE PLAY ..............................3-18
CHECKING THE SPARK PLUG .............................................................3-18
CHECKING THE IGNITION TIMING.......................................................3-20
MEASURING THE COMPRESSION PRESSURE.................................. 3-21
CHECKING THE ENGINE OIL LEVEL....................................................3-23
CHANGING THE ENGINE OIL ...............................................................3-24
CHANGING THE TRANSMISSION OIL..................................................3-27
REPLACING THE AIR FILTER ELEMENTS...........................................3-28
CLEANING THE V-BELT CASE AIR FILTER ELEMENT .......................3-29
CHECKING THE THROTTLE BODY JOINT AND
INTAKE MANIFOLD ...............................................................................3-30
CHECKING THE FUEL HOSE ................................................................3-30
CHECKING THE BREATHER HOSES ...................................................3-31
CHECKING THE EXHAUST SYSTEM....................................................3-32
CHECKING THE COOLANT LEVEL.......................................................3-32
CHECKING THE COOLING SYSTEM ....................................................3-33
CHANGING THE COOLANT...................................................................3-34
CHASSIS .......................................................................................................3-37
ADJUSTING THE REAR BRAKE LOCK LEVER CABLE .......................3-37
CHECKING THE BRAKE FLUID LEVEL.................................................3-38
CHECKING THE FRONT AND REAR BRAKE PADS ............................3-39
CHECKING THE FRONT AND REAR BRAKE HOSES..........................3-39
BLEEDING THE HYDRAULIC BRAKE SYSTEM ...................................3-40
CHECKING AND ADJUSTING THE STEERING HEAD .........................3-41
CHECKING THE FRONT FORK .............................................................3-43
CHECKING THE TIRES..........................................................................3-44
CHECKING THE WHEELS .....................................................................3-47
CHECKING AND LUBRICATING THE CABLES ....................................3-47
LUBRICATING THE LEVERS .................................................................3-48
LUBRICATING THE SIDESTAND...........................................................3-48
LUBRICATING THE CENTERSTAND ....................................................3-48
ELECTRICAL SYSTEM.................................................................................3-49
CHECKING AND CHARGING THE BATTERY.......................................3-49
CHECKING THE FUSES ........................................................................3-54
REPLACING THE HEADLIGHT BULBS .................................................3-56
ADJUSTING THE HEADLIGHT BEAMS................................................. 3-58

CHAPTER 4
CHASSIS
FRONT WHEEL AND BRAKE DISC...............................................................4-1
REMOVING THE FRONT WHEEL............................................................4-3
CHECKING THE FRONT WHEEL ............................................................4-3
CHECKING THE BRAKE DISCS ..............................................................4-4
INSTALLING THE FRONT WHEEL ..........................................................4-6
ADJUSTING THE FRONT WHEEL STATIC BALANCE ...........................4-7
REAR WHEEL AND BRAKE DISC.................................................................4-9
REMOVING THE REAR WHEEL ............................................................4-10
CHECKING THE REAR WHEEL.............................................................4-10
ADJUSTING THE REAR WHEEL STATIC BALANCE............................4-10
FRONT AND REAR BRAKES.......................................................................4-11
FRONT BRAKE PADS ............................................................................4-11
REAR BRAKE PADS...............................................................................4-12
REPLACING THE FRONT BRAKE PADS ..............................................4-13
REPLACING THE REAR BRAKE PADS.................................................4-15
FRONT BRAKE MASTER CYLINDER....................................................4-18
REAR BRAKE MASTER CYLINDER ......................................................4-21
DISASSEMBLING THE FRONT BRAKE MASTER CYLINDER .............4-24
DISASSEMBLING THE REAR BRAKE MASTER CYLINDER................4-24
CHECKING THE FRONT AND REAR BRAKE
MASTER CYLINDERS ...........................................................................4-25
ASSEMBLING AND INSTALLING THE FRONT BRAKE
MASTER CYLINDER .............................................................................4-26
ASSEMBLING AND INSTALLING THE REAR BRAKE
MASTER CYLINDER .............................................................................4-28
FRONT BRAKE CALIPER.......................................................................4-31
REAR BRAKE CALIPER .........................................................................4-33
DISASSEMBLING THE FRONT BRAKE CALIPER ................................4-36
DISASSEMBLING THE REAR BRAKE CALIPER ..................................4-36
CHECKING THE FRONT AND REAR BRAKE CALIPERS ....................4-37
ASSEMBLING AND INSTALLING THE FRONT BRAKE CALIPER .......4-39
ASSEMBLING AND INSTALLING THE REAR BRAKE CALIPER..........4-41
FRONT FORK................................................................................................4-44
REMOVING THE FRONT FORK LEGS..................................................4-48
DISASSEMBLING THE FRONT FORK LEGS ........................................4-48
CHECKING THE FRONT FORK LEGS ..................................................4-50
ASSEMBLING THE FRONT FORK LEGS ..............................................4-50
INSTALLING THE FRONT FORK LEGS ................................................4-53
HANDLEBAR ................................................................................................4-54
REMOVING THE HANDLEBAR..............................................................4-56
CHECKING THE HANDLEBAR ..............................................................4-56
INSTALLING THE HANDLEBAR ............................................................4-56

STEERING HEAD..........................................................................................4-60
LOWER BRACKET .................................................................................4-60
REMOVING THE LOWER BRACKET.....................................................4-62
CHECKING THE STEERING HEAD .......................................................4-63
INSTALLING THE STEERING HEAD .....................................................4-64
REAR SHOCK ABSORBER ASSEMBLIES AND SWINGARM...................4-65
REMOVING THE REAR SHOCK ABSORBER ASSEMBLIES ...............4-67
CHECKING THE REAR SHOCK ABSORBER ASSEMBLIES................4-67
INSTALLING THE REAR SHOCK ABSORBER ASSEMBLIES..............4-67
REMOVING THE SWINGARM................................................................4-68
CHECKING THE SWINGARM ................................................................4-68
INSTALLING THE SWINGARM ..............................................................4-69
CHAPTER 5
ENGINE
ENGINE REMOVAL ........................................................................................5-1
LEADS, HOSES, EXHAUST PIPE AND MUFFLER .................................5-1
ENGINE.....................................................................................................5-3
INSTALLING THE ENGINE.......................................................................5-5
CAMSHAFTS...................................................................................................5-6
CYLINDER HEAD COVER........................................................................5-6
CAMSHAFTS ............................................................................................5-7
REMOVING THE CAMSHAFTS................................................................5-9
CHECKING THE CAMSHAFTS ..............................................................5-10
CHECKING THE CAMSHAFT SPROCKETS .........................................5-12
CHECKING THE DECOMPRESSION SYSTEM.....................................5-12
CHECKING THE TIMING CHAIN TENSIONER......................................5-13
INSTALLING THE CAMSHAFTS ............................................................5-13
CYLINDER HEAD..........................................................................................5-17
REMOVING THE CYLINDER HEAD.......................................................5-19
CHECKING THE CYLINDER HEAD .......................................................5-19
CHECKING THE TIMING CHAIN GUIDE (EXHAUST SIDE) .................5-20
INSTALLING THE CYLINDER HEAD .....................................................5-20
VALVES AND VALVE SPRINGS..................................................................5-21
REMOVING THE VALVES......................................................................5-22
CHECKING THE VALVES AND VALVE GUIDES ..................................5-23
CHECKING THE VALVE SEATS ............................................................5-25
CHECKING THE VALVE SPRINGS........................................................5-27
CHECKING THE VALVE LIFTERS .........................................................5-28
INSTALLING THE VALVES ....................................................................5-28

CYLINDER AND PISTON..............................................................................5-30
REMOVING THE PISTON ......................................................................5-31
CHECKING THE CYLINDER AND PISTON ...........................................5-31
CHECKING THE PISTON RINGS...........................................................5-33
CHECKING THE PISTON PIN ................................................................5-34
INSTALLING THE PISTON AND CYLINDER .........................................5-34
BELT DRIVE..................................................................................................5-37
V-BELT CASE COVER ...........................................................................5-37
V-BELT AND PRIMARY/SECONDARY SHEAVE...................................5-38
SECONDARY SHEAVE ..........................................................................5-40
REMOVING THE PRIMARY SHEAVE....................................................5-42
REMOVING THE SECONDARY SHEAVE AND V-BELT .......................5-42
DISASSEMBLING THE SECONDARY SHEAVE....................................5-43
CHECKING THE V-BELT........................................................................5-44
CHECKING THE V-BELT CASE AIR DUCTS.........................................5-44
CHECKING THE PRIMARY SHEAVE ....................................................5-44
CHECKING THE PRIMARY SHEAVE WEIGHTS...................................5-44
CHECKING THE SECONDARY SHEAVE ..............................................5-45
CHECKING THE CLUTCH SHOES ........................................................5-45
ASSEMBLING THE PRIMARY SHEAVE ................................................5-46
ASSEMBLING THE SECONDARY SHEAVE..........................................5-46
INSTALLING THE SECONDARY SHEAVE, V-BELT
AND PRIMARY SHEAVE ....................................................................... 5-47
STARTER CLUTCH AND GENERATOR......................................................5-49
GENERATOR ROTOR COVER AND STATOR COIL ............................5-49
STARTER CLUTCH AND GENERATOR................................................5-51
REMOVING THE GENERATOR .............................................................5-52
CHECKING THE STARTER CLUTCH ....................................................5-53
INSTALLING THE STARTER CLUTCH ..................................................5-54
INSTALLING THE GENERATOR............................................................5-54
OIL PUMP......................................................................................................5-56
CHECKING THE OIL PUMP ...................................................................5-57
CHECKING THE OIL PUMP DRIVE CHAIN ...........................................5-57
ASSEMBLING THE OIL PUMP...............................................................5-58
INSTALLING THE OIL PUMP .................................................................5-58

CRANKSHAFT ..............................................................................................5-59
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT ASSEMBLY......5-59
CRANKCASE BEARINGS.......................................................................5-61
DISASSEMBLING THE CRANKCASE....................................................5-62
REMOVING THE CRANKSHAFT JOURNAL BEARINGS ......................5-62
CHECKING THE CRANKSHAFT AND CONNECTING ROD .................5-63
CHECKING THE BALANCER SHAFT ASSEMBLY................................ 5-66
CHECKING THE CRANKCASE ..............................................................5-66
CHECKING THE TIMING CHAIN AND TIMING CHAIN GUIDE
(INTAKE SIDE).......................................................................................5-67
CHECKING THE OIL PUMP GEARS AND SHAFTS..............................5-67
CHECKING THE RELIEF VALVE ...........................................................5-67
CHECKING THE BEARINGS AND OIL SEALS...................................... 5-67
CHECKING THE CIRCLIPS AND WASHERS ........................................5-68
INSTALLING THE CRANKSHAFT JOURNAL BEARINGS.....................5-68
INSTALLING THE CRANKSHAFT ASSEMBLY AND BALANCER
SHAFT ASSEMBLY ...............................................................................5-69
ASSEMBLING THE CRANKCASE..........................................................5-69
TRANSMISSION............................................................................................5-71
CHECKING THE TRANSMISSION .........................................................5-73
INSTALLING THE PRIMARY DRIVE GEAR OIL SEAL..........................5-73
CHAPTER 6
COOLING SYSTEM
RADIATOR ......................................................................................................6-1
CHECKING THE RADIATOR....................................................................6-2
INSTALLING THE RADIATOR..................................................................6-3
THERMOSTAT ................................................................................................6-4
CHECKING THE THERMOSTAT..............................................................6-5
INSTALLING THE THERMOSTAT............................................................6-6
WATER PUMP AND OIL COOLER ................................................................6-7
CHECKING THE WATER PUMP ..............................................................6-9
CHECKING THE OIL COOLER ................................................................6-9
ASSEMBLING THE WATER PUMP........................................................6-10

CHAPTER 7
FUEL INJECTION SYSTEM
FUEL INJECTION SYSTEM............................................................................7-1
WIRING DIAGRAM ...................................................................................7-2
ECU’S SELF-DIAGNOSTIC FUNCTION...................................................7-3
ALTERNATE INSTRUCTIONS OPERATION CONTROL
(FAIL-SAFE ACTION) ..............................................................................7-4
FAIL-SAFE ACTIONS TABLE ...................................................................7-4
TROUBLESHOOTING CHART .................................................................7-6
DIAGNOSTIC MODE ................................................................................7-7
TROUBLESHOOTING DETAILS ............................................................7-12
THROTTLE BODY AND FUEL INJECTOR ..................................................7-25
THROTTLE BODY AND FUEL INJECTOR.............................................7-25
FUEL HOSE ............................................................................................7-27
FUEL TANK.............................................................................................7-28
REMOVING THE FUEL HOSE ...............................................................7-30
REMOVING THE FUEL PUMP ...............................................................7-30
CHECKING THE FUEL INJECTOR ........................................................7-31
CHECKING THE THROTTLE BODY ......................................................7-31
INSTALLING THE FUEL PUMP..............................................................7-32
INSTALLING THE SUB-FRAME .............................................................7-32
INSTALLING THE FUEL HOSE ..............................................................7-33
CHECKING THE FUEL PUMP AND PRESSURE
REGULATOR OPERATION ...................................................................7-34
CHECKING THE THROTTLE POSITION SENSOR ...............................7-34
CHECKING THE ISC (IDLE SPEED CONTROL) VALVE.......................7-36
AIR INDUCTION SYSTEM ............................................................................7-37
AIR INJECTION.......................................................................................7-37
AIR CUT-OFF VALVE .............................................................................7-37
AIR INDUCTION SYSTEM DIAGRAMS.................................................. 7-38
AIR CUT-OFF VALVE AND AIR INDUCTION SYSTEM HOSES ...........7-39
CHECKING THE AIR INDUCTION SYSTEM..........................................7-40
CANISTER.....................................................................................................7-41
CHAPTER 8
ELECTRICAL SYSTEM
ELECTRICAL COMPONENTS........................................................................8-1
CHECKING SWITCH CONTINUITY................................................................8-3
CHECKING THE SWITCHES..........................................................................8-4

CHECKING THE BULBS AND BULB SOCKETS ..........................................8-5
TYPES OF BULBS ....................................................................................8-5
CHECKING THE CONDITION OF THE BULBS .......................................8-6
CHECKING THE CONDITION OF THE BULB SOCKETS .......................8-7
IGNITION SYSTEM .........................................................................................8-8
CIRCUIT DIAGRAM ..................................................................................8-8
TROUBLESHOOTING ..............................................................................8-9
ELECTRIC STARTING SYSTEM ..................................................................8-14
CIRCUIT DIAGRAM ................................................................................8-14
STARTING CIRCUIT CUT-OFF SYSTEM OPERATION ........................8-15
TROUBLESHOOTING ............................................................................8-16
STARTER MOTOR........................................................................................8-19
CHECKING THE STARTER MOTOR .....................................................8-21
ASSEMBLING THE STARTER MOTOR.................................................8-22
CHARGING SYSTEM....................................................................................8-23
CIRCUIT DIAGRAM ................................................................................8-23
TROUBLESHOOTING ............................................................................8-24
LIGHTING SYSTEM ......................................................................................8-26
CIRCUIT DIAGRAM ................................................................................8-26
TROUBLESHOOTING ............................................................................8-27
CHECKING THE LIGHTING SYSTEM....................................................8-29
SIGNALING SYSTEM ...................................................................................8-34
CIRCUIT DIAGRAM ................................................................................8-34
TROUBLESHOOTING ............................................................................8-36
CHECKING THE SIGNALING SYSTEM .................................................8-37
COOLING SYSTEM.......................................................................................8-44
CIRCUIT DIAGRAM ................................................................................8-44
TROUBLESHOOTING ............................................................................8-45
CHAPTER 9
TROUBLESHOOTING
STARTING FAILURE/HARD STARTING .......................................................9-1
ENGINE.....................................................................................................9-1
FUEL SYSTEM..........................................................................................9-1
ELECTRICAL SYSTEMS ..........................................................................9-2

INCORRECT ENGINE IDLING SPEED...........................................................9-2
ENGINE.....................................................................................................9-2
FUEL SYSTEM..........................................................................................9-2
ELECTRICAL SYSTEMS ..........................................................................9-2
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE .................................9-3
ENGINE.....................................................................................................9-3
FUEL SYSTEM..........................................................................................9-3
FAULTY CLUTCH ...........................................................................................9-3
ENGINE OPERATES BUT SCOOTER WILL NOT MOVE........................9-3
CLUTCH SLIPS.........................................................................................9-3
POOR STARTING PERFORMANCE........................................................9-3
POOR SPEED PERFORMANCE.............................................................. 9-3
OVERHEATING...............................................................................................9-4
ENGINE.....................................................................................................9-4
COOLING SYSTEM ..................................................................................9-4
FUEL SYSTEM..........................................................................................9-4
CHASSIS...................................................................................................9-4
ELECTRICAL SYSTEMS ..........................................................................9-4
OVERCOOLING ..............................................................................................9-4
COOLING SYSTEM ..................................................................................9-4
POOR BRAKING PERFORMANCE................................................................9-5
FAULTY FRONT FORK LEGS........................................................................9-5
LEAKING OIL ............................................................................................9-5
MALFUNCTION.........................................................................................9-5
UNSTABLE HANDLING..................................................................................9-5
FAULTY LIGHTING OR SIGNALING SYSTEM..............................................9-6
HEADLIGHT DOES NOT COME ON ........................................................9-6
HEADLIGHT BULB BURNT OUT..............................................................9-6
TAIL/BRAKE LIGHT DOES NOT COME ON ............................................9-6
TAIL/BRAKE LIGHT BULB BURNT OUT..................................................9-6
TURN SIGNAL DOES NOT COME ON ....................................................9-6
TURN SIGNAL BLINKS SLOWLY.............................................................9-6
TURN SIGNAL REMAINS LIT...................................................................9-6
TURN SIGNAL BLINKS QUICKLY............................................................9-6
HORN DOES NOT SOUND ......................................................................9-6

1 - 1
GEN
INFO
EAS00015
GENERAL INFORMATION
SCOOTER IDENTIFICATION
EAS00017
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1is
stamped into the frame.
1
EAS00018
MODEL LABEL
The model label 1is affixed inside the storage
box. Record the information on this label in the
space provided. This information will be
needed when ordering spare parts.
1
SCOOTER IDENTIFICATION

1 - 2
GEN
INFO
FEATURES
EAS00896
FEATURES
OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera-
ture. In the conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the
combustion chamber is created by the volume of the intake air and the fuel that is metered by the jet
used in the respective carburetor.
Despite the same volume of intake air, the fuel volume requirement varies by the engine operating
conditions, such as acceleration, deceleration, or operating under a heavy load. Carburetors that
meter the fuel through the use of jets have been provided with various auxiliary devices, so that an
optimum air-fuel ratio can be achieved to accommodate the constant changes in the operating con-
ditions of the engine.
As the requirements for the engine to deliver more performance and cleaner exhaust gases
increase, it becomes necessary to control the air-fuel ratio in a more precise and finely tuned man-
ner. To accommodate this need, this model has adopted an electronically controlled fuel injection
(FI) system, in place of the conventional carburetor system. This system can achieve an optimum
air-fuel ratio required by the engine at all times by using a microprocessor that regulates the fuel
injection volume according to the engine operating conditions detected by various sensors.
The adoption of the FI system has resulted in a highly precise fuel supply, improved engine
response, better fuel economy, and reduced exhaust emissions.
1ECU
2Fuel injection system
relay
3Engine trouble warn-
ing light
4Lean angle cut-off
switch
5Fuel hose
6Ignition coil
7Fuel injector
8Intake air pressure
sensor
9Throttle position sen-
sor
0ISC (idle speed con-
trol) valve
AIntake air temperature
sensor
BBattery
CAir filter case
DCatalytic converter
ECrankshaft position
sensor
FCoolant temperature
sensor
GSpark plug
HFuel tank
IFuel pump
3
5
6
780
A
9B
C
2
1
4
D
E
F
G
H
I
1

1 - 3
GEN
INFO
FEATURES
EAS00897
FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains
the fuel pressure that is applied to the fuel injector at only 250 kPa (2.5 kg/cm2, 35.6 psi). Accord-
ingly, when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens,
causing the fuel to be injected into the intake manifold only during the time the passage remains
open. Therefore, the longer the length of time the fuel injector is energized (injection duration), the
greater the volume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector
is energized (injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from
the throttle position sensor, crankshaft position sensor, intake air pressure sensor, intake tempera-
ture sensor and coolant temperature sensor enable the ECU to determine the injection duration.
The injection timing is determined through the signals from the crankshaft position sensor. As a
result, the volume of fuel that is required by the engine can be supplied at all times in accordance
with the driving conditions.
1Fuel pump
2Fuel injector
3Ignition coil
4ECU
5Catalytic converter
6Coolant temperature
sensor
7Crankshaft position
sensor
8Intake air pressure
sensor
9Throttle body
0Intake air temperature
sensor
AAir filter case
BThrottle position sen-
sor
CISC (idle speed con-
trol) valve
ÈFuel system
ÉAir system
ÊControl system
1
2
3
C
B
5
6
7
8
9
0
A
4
È
É
Ê
Illustration is for reference only.

1 - 4
GEN
INFO
FEATURES
INSTRUMENT FUNCTIONS
Multifunction display
WARNING
Be sure to stop the vehicle before making any
setting changes to the multifunction display.
1Clock/ambient temperature display
2Coolant temperature meter
3Fuel meter
4Odometer/tripmeters
5“SELECT” button
6“RESET” button
1V-belt replacement indicator “V-BELT”
2Fuel level warning symbol “ ”
3Coolant temperature symbol “ ”
4Oil change indicator “OIL”
The multifunction display is equipped with the
following:
• a fuel meter
• a coolant temperature meter
• an odometer (which shows the total dis-
tance traveled)
• two tripmeters (which show the distance
traveled since they were last set to zero)
• a fuel reserve tripmeter (which shows the
distance traveled since the bottom segment
of the fuel meter and fuel level warning
symbol started flashing)
• a self-diagnosis device
•aclock
• an ambient temperature display
• an oil change indicator
• a V-belt replacement indicator
NOTE:
• Be sure to turn the key to “ON” before using
the “SELECT” and “RESET” buttons.
• When the key is turned to “ON”, all of the dis-
play segments of the multifunction display
will appear one after the other and then dis-
appear, in order to test the electrical circuit.
CAUTION:
If bars 1appear where the odometer and
tripmeters are normally displayed, the
multi-function display is malfunctioning.
Replace the entire multi-function display.
1
2
3
5
6
4
3412
1