Yamaha YBR250 2007 User manual

YBR250
SERVICE MANUAL
5D1-F8197-E0
2007

YBR250
SERVICE MANUAL
©2007 Yamaha Motor da Amazônia Ltda.
First edition, February 2007
All rights reserved.
Any reproduction or unauthorized use without
the written permission of Yamaha Motor da
Amazônia Ltda is expressly prohibited.

NOTICE
This manual was produced by the YAMAHA MOTOR DA AMAZÔNIA LTDA., 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. 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.
YAMAHA MOTOR DA AMAZÔNIA LTDA. is continually striving to improve all of its models. Modifi-
cations 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.
NOTE:
Designs and specifications are subject to change without notice.
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 vehicle operator, a bystander or a person checking or repairing the vehicle.
A CAUTION indicates special precautions that must be taken to avoid damage
to the vehicle.
A NOTE provides key information to make procedures easier or clearer.
VV
VV
V
CAUTION:
VV
VV
VWARNING
NOTE:

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.
1 The manual is divided into chapters. An abbreviation and symbol in the upper right corner of each
page indicate the current chapter.
2 Each 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.
3 Sub-section titles appear in smaller print than the section title.
4 To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section.
5 Numbers are given in the order of the jobs in the exploded diagram. A circled number indicates a
disassembly step.
6 Symbols indicate parts to be lubricated or replaced.
Refer to “SYMBOLS”.
7 A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
8 Jobsrequiringmoreinformation(suchasspecialtoolsandtechnicaldata)aredescribedsequentially.
8
1
23
4
5
6
7

SYMBOLS
The following symbols are not common to all
vehicles
Symbols 1- 8indicate the subject of each
chapter.
1Generalinformation
2Specifications
3Periodic checks and adjustments
4Chassis
5Engine
6Fuel Injection system
7Electrical system
8Troubleshooting
Symbols 9- Findicate the following:
9Serviceable with engine mounted
0Fillingfluid
ALubricant
BSpecial tool
CTighteningtorque
DClearance, wear limit
EEngine speed
FElectrical data
SymbolsG-Nin theexploded diagrams indi-
cate the types of lubricants and lubrication
points.
GEngineoil
HGear oil
IMolybdenum-disulphideoil
JBrake fluid
KWheel-bearinggrease
LLithium-soap-based grease
MMolybdenum-disulphidegrease
NSilicone grease
SymbolsO- Pinthe explodeddiagrams indi-
cate the following.
OApply locking agent (LOCTITE®)
PReplace the part.
12
34
56
78
F
KM
OP
GI
L
H
New
GEN
INFO SPEC
CHK
ADJ
ENG
CHAS
ELEC ?
TRBL
SHTG
E
DC
B
A
FI
90
J
N

TABLE OF CONTENTS
?8
7
6
5
4
3
GEN
INFO 1
2
PERIODIC CHECKS
AND ADJUSTMENTS
GENERALINFORMATION
SPECIFICATIONS
CHASSIS
ELECTRICAL SYSTEM
TROUBLESHOOTING
ENGINE
FUEL INJECTION SYSTEM
SPEC
CHK
ADJ
CHAS
ENG
FI
ELEC
TRBL
SHTG

CHAPTER 1
GENERALINFORMATION
VEHICLE IDENTIFICATION......................................................................... 1-1
VEHICLE IDENTIFICATION NUMBER................................................... 1-1
MODEL LABEL ........................................................................................ 1-1
FEATURES .................................................................................................... 1-2
FEATURES .............................................................................................. 1-2
FI SYSTEM .............................................................................................. 1-3
IMPORTANT INFORMATION ....................................................................... 1-4
PREPARATION FOR REMOVAL AND DISASSEMBLY........................ 1-4
REPLACEMENT PARTS......................................................................... 1-4
GASKETS, OIL SEALS AND O-RINGS.................................................. 1-4
LOCK WASHERS, PLATES AND COTTER PINS ................................ 1-5
BEARINGS AND OIL SEALS .................................................................. 1-5
CIRCLIPS................................................................................................. 1-5
CHECKING THE CONNECTIONS ............................................................... 1-6
SPECIAL TOOLS .......................................................................................... 1-7

GEN
INFO
VEHICLE IDENTIFICATION
VEHICLE IDENTIFICATION NUMBER
Chassis serial number 1is stamped into the right
side of the steering head pipe.
VEHICLE IDENTIFICATION
MODEL LABEL
The model label (1) is affixed to the frame.
Thisinformation will beneeded to orderspare parts.
1-1
1
1

GEN
INFO
FEATURES
Themain functionof afuel supplysystem isto providefuel tothe combustionchamber atthe optimum
air-fuel ratio in accordance with the engine operating conditions and the atmospheric temperature. 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 that is used
in the respective chamber.
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
conditions 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 manner. To
accommodatethis need, this model has adopted anelectronically controlledfuel 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.
FEATURES
1ECU (engine control
unit)
2Engine trouble
warning light
3Lean angle sensor
4Fuel delivery hose
5Ignition coil
6Fuel injector
7FID (fast idle
solenoid)
8Throttle body sensor
assembly
9Battery
0Air filter case
ACatalytic converter
BCrankshaft position
sensor
CEngine temperature
sensor
DSpark plug
EFuel tank
FFuel pump
GAir induction system
(A.I.System)
HO2 sensor
1-2
2E
57F
4931
BC8 0
6
DA
GH