Yamaha YFM70RY User manual

2009
SERVICE MANUAL
YFM70RY
1S3-28197-E2

EAS20040
YFM70RY
SERVICE MANUAL
©2008 by Yamaha Motor Co., Ltd.
First edition, June 2008
All rights reserved.
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd.
is expressly prohibited.

EAS20071
IMPORTANT
This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha dealers
and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in one man-
ual. 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 vehi-
cle 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 vehi-
cle 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 sig-
nificant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and
will appear in future editions of this manual where applicable.
T
IP
• This Service Manual contains information regarding periodic maintenance to the emission control sys-
tem. Please read this material carefully.
• Designs and specifications are subject to change without notice.
EAS20081
IMPORTANT MANUAL INFORMATION
Particularly important information is distinguished in this manual by the following notations.
This is the safety alert symbol. It is used to alert you to potential person-
al injury hazards. Obey all safety messages that follow this symbol to
avoid possible injury or death.
A WARNING indicates a hazardous situation which, if not avoided, could
result in death or serious injury.
A NOTICE indicates special precautions that must be taken to avoid
damage to the vehicle or other property.
A TIP provides key information to make procedures easier or clearer.
WARNING
NOTICE
TIP

EAS20090
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.
•The manual is divided into chapters and each chapter is divided into sections. The current section title
“1”is shown at the top of each page.
•Sub-section titles “2”appear in smaller print than the section title.
•To help identify parts and clarify procedure steps, there are exploded diagrams “3”at the start of each
removal and disassembly section.
•Numbers “4”are given in the order of the jobs in the exploded diagram. A number indicates a disas-
sembly step.
•Symbols “5”indicate parts to be lubricated or replaced.
Refer to “SYMBOLS”.
•A job instruction chart “6”accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
•Jobs “7”requiring more information (such as special tools and technical data) are described sequen-
tially.
1
4
3
5
6
7
2

EAS20100
SYMBOLS
The following symbols are used in this manual
for easier understanding.
T
IP
The following symbols are not relevant to every
vehicle.
G
M
E
BLS
M
910
11 12
13 14
15 16
17 18
LT New
BF
S
T
R
.
.
123
456
78
1. Serviceable with engine mounted
2. Filling fluid
3. Lubricant
4. Special tool
5. Tightening torque
6. Wear limit, clearance
7. Engine speed
8. Electrical data
9. Engine oil
10.Gear oil
11. Molybdenum disulfide oil
12. Brake fluid
13.Wheel bearing grease
14. Lithium-soap-based grease
15. Molybdenum disulfide grease
16.Silicone grease
17.Apply locking agent (LOCTITE®).
18. Replace the part with a new one.

EAS20110 TABLE OF CONTENTS
GENERAL INFORMATION 1
SPECIFICATIONS 2
PERIODIC CHECKS AND
ADJUSTMENTS 3
CHASSIS 4
ENGINE 5
COOLING SYSTEM 6
FUEL SYSTEM 7
ELECTRICAL SYSTEM 8
TROUBLESHOOTING 9

1
GENERAL INFORMATION
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
SELF-ADJUSTING PARKING BRAKE MECHANISM...............................1-4
PARKING BRAKE OPERATION ............................................................... 1-5
INSTRUMENT FUNCTIONS .....................................................................1-7
IMPORTANT INFORMATION .........................................................................1-8
PREPARATION FOR REMOVAL AND DISASSEMBLY........................... 1-8
REPLACEMENT PARTS...........................................................................1-8
GASKETS, OIL SEALS AND O-RINGS ....................................................1-8
LOCK WASHERS/PLATES AND COTTER PINS .....................................1-8
BEARINGS AND OIL SEALS ....................................................................1-9
CIRCLIPS ..................................................................................................1-9
CHECKING THE CONNECTIONS ................................................................1-10
SPECIAL TOOLS ..........................................................................................1-11

IDENTIFICATION
1-1
EAS20130
IDENTIFICATION
EAS20140
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number “1”is stamped
into the left side of the frame.
EAS20150
MODEL LABEL
The model label “1”is affixed to the air filter case
cover. This information will be needed to order
spare parts.
1
1

FEATURES
1-2
EAS20170
FEATURES
EAS1S3L001
OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the 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 used in the
respective carburetor.
Despite the same volume of intake air, the fuel volume requirement varies with 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 accom-
modate 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.
12 345 6 78910 11 12
13
14
15161718
1. Engine trouble warning light
2. Ignition coil
3. Fuel tank
4. Fuel hose
5. Fuel pump
6. Intake air pressure sensor
7. Lean angle sensor
8. Battery
9. Intake air temperature sensor
10.ECU (electronic control unit)
11.Air filter case
12.Relay unit (fuel pump relay)
13.Speed sensor
14. Throttle position sensor
15.Crankshaft position sensor
16. Fuel injector
17. Coolant temperature sensor
18. Spark plug

FEATURES
1-3
EAS1S3L002
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 324 kPa (3.24 kg/cm², 46.1 psi). Accordingly,
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. There-
fore, the longer the length of time the fuel injector is energized (injection duration), the greater the vol-
ume 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 air temperature
sensor, coolant temperature sensor and speed sensor enable the ECU to determine the injection du-
ration. 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.
Illustration is for reference only.
10
2
1
3
12
5
6
7
8
9
A
B
C
11
4
1. Fuel pump
2. Fuel injector
3. Ignition coil
4. ECU (electronic control unit)
5. Coolant temperature sensor
6. Crankshaft position sensor
7. Intake air pressure sensor
8. Throttle body
9. Intake air temperature sensor
10.Air filter case
11.Throttle position sensor
12.Speed sensor
A. Fuel system
B. Air system
C. Control system

FEATURES
1-4
EAS1S3L003
SELF-ADJUSTING PARKING BRAKE MECHANISM
Usually, for vehicles equipped with a parking brake that must be adjusted manually, it is necessary to
adjust the adjusting bolt “5”to achieve the proper clearance between the brake caliper piston “7”and
the adjusting bolt.
This adjustment procedure is unnecessary for vehicles equipped with a self-adjusting parking brake
mechanism. The proper clearance is automatically maintained at all times, ensuring stable braking per-
formance when parking the vehicle.
1
2
3
4
5
67
1. Parking brake arm
2. Parking brake shaft
3. Adjusting bolt
4. Adjusting bolt sleeve
5. Adjusting bolt
6. Nut
7. Brake caliper piston

FEATURES
1-5
EAS1S3L004
PARKING BRAKE OPERATION
When the parking brake is operated, the parking brake cable turns the parking brake arm “1”. The ro-
tation of the parking brake arm is changed to axial thrust in the parking brake shaft “2”and the adjusting
bolt “3”is pushed against the adjusting bolt sleeve “4”.
When the adjusting bolt sleeve receives the force, the dark shaded area in the above illustration is
pushed and the brake pad “6”is pushed against the brake disc.
When the brake pad wears, the clearance between the brake caliper piston “5”and the brake pad be-
comes larger and the force applied to the brake pad becomes weaker.
If this occurs, the self-adjusting parking brake mechanism adjusts automatically to achieve the proper
clearance.
1
2
3
4
5
6
1. Parking brake arm
2. Parking brake shaft
3. Adjusting bolt
4. Adjusting bolt sleeve
5. Brake caliper piston
6. Brake pad

FEATURES
1-6
When the brake pedal is operated, the brake fluid pressure in the master cylinder increases and the
brake caliper piston “1”and the nut “2”are pushed.
When there is proper clearance between the brake caliper piston and the brake pad, no other parts
move because the movement of the brake caliper piston and the nut is absorbed by the backlash of the
threads of the nut and the adjusting bolt “3”.
When the movement of the nut is greater than the backlash between the nut and the adjusting bolt, the
parking brake adjusts automatically.
The amount of the adjustment varies with brake fluid pressure. Operating the parking brake makes no
adjustment.
The adjustment operation is as follows.
1. When the brake pedal is operated, the brake fluid pressure increases and the brake caliper piston
and the nut move.
2. When the movement of the brake caliper piston and the nut is greater than the backlash of the
threads of the nut and the adjusting bolt, the force “A”will be required to pull the adjusting bolt.
The force to pull the adjusting bolt will be turned into the rotation torque “B”by the shape of the
threads of the nut and the adjusting bolt.
3. At this time, the clutch torque “C”between the adjusting bolt and the adjusting bolt sleeve “4”will
decrease depending on the force required to pull the adjusting bolt.
When the rotation torque exceeds the clutch torque, the adjusting bolt rotates and the clearance be-
tween the brake caliper piston and the brake pad decreases by the movement of the threads of the
nut and the adjusting bolt.
12
3
4
A
B
C
1. Brake caliper piston
2. Nut
3. Adjusting bolt
4. Adjusting bolt sleeve

FEATURES
1-7
EAS1S3L005
INSTRUMENT FUNCTIONS
Multi-function display
The multi-function display is equipped with the
following:
•a speedometer (which shows the riding speed)
•an odometer (which shows the total distance
traveled)
•two tripmeters (which show the distance trav-
eled since they were last set to zero)
•a clock
•an hour meter (which shows the total time the
engine has been running)
•a self-diagnosis device
Odometer and tripmeter modes
Pushing the “SELECT”button switches the dis-
play between the odometer mode “ODO”and
the tripmeter modes “A”and “B”in the following
order:
ODO →TRIP A →TRIP B →ODO
To reset a tripmeter, select it by pushing the “SE-
LECT”button, and then push the “RESET”but-
ton for at least three seconds. The tripmeters
can be used to estimate the distance that can be
traveled with a full tank of fuel. This information
will enable you to plan future fuel stops.
T
IP
Pushing and holding in the “SELECT”button,
and turning the key to “ON”while the button is
pushed, switches the display between “mph”
and “km/h”.
Clock mode
Pushing the “CLOCK”button for at least three
seconds to switch the display between the clock
mode “CLOCK”and the hour meter mode
“HOUR”in the following order:
CLOCK →HOUR →CLOCK
To set the clock:
1. Set the display to the clock mode.
2. Push the “SELECT”button and “RESET”but-
ton together for at least three seconds.
3. When the hour digits start flashing, push the
“RESET”button to set the hours.
4. Push the “SELECT”button, and the minute
digits will start flashing.
5. Push the “RESET”button to set the minutes.
6. Push the “SELECT”button and then release
it to start the clock.
Self-diagnosis device
This model is equipped with a self-diagnosis de-
vice for various electrical circuits.
If any of those circuits are defective, the multi-
function display will indicate a two-digit fault
code. If the multi-function display indicates such
a fault code, note the code number, and then
check the vehicle.
NOTICE
ECA1S3L024
If the multi-function display indicates a fault
code, the vehicle should be checked as soon
as possible in order to avoid engine damage.
1. “RESET”button
2. “SELECT”button
3. Speedometer
4. Clock/Hour meter
5. Odometer/Tripmeter A/Tripmeter B
2
1
34
5
1. Fault code display
1

IMPORTANT INFORMATION
1-8
EAS20180
IMPORTANT INFORMATION
EAS20190
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Before removal and disassembly, remove all
dirt, mud, dust and foreign material.
2. Use only the proper tools and cleaning equip-
ment.
Refer to “SPECIAL TOOLS”on page 1-11.
3. When disassembling, always keep mated
parts together. This includes gears, cylinders,
pistons and other parts that have been “mat-
ed”through normal wear. Mated parts must
always be reused or replaced as an assem-
bly.
4. During disassembly, clean all of the parts and
place them in trays in the order of disassem-
bly. This will speed up assembly and allow for
the correct installation of all parts.
5. Keep all parts away from any source of fire.
EAS20200
REPLACEMENT PARTS
Use only genuine Yamaha parts for all replace-
ments. Use oil and grease recommended by
Yamaha for all lubrication jobs. Other brands
may be similar in function and appearance, but
inferior in quality.
EAS20210
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets, seals and O-rings. All gasket surfac-
es, oil seal lips and O-rings must be cleaned.
2. During reassembly, properly oil all mating
parts and bearings and lubricate the oil seal
lips with grease.
EAS20220
LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace all lock washers/plates
“1”and cotter pins. After the bolt or nut has been
tightened to specification, bend the lock tabs
along a flat of the bolt or nut.
1. Oil
2. Lip
3. Spring
4. Grease

IMPORTANT INFORMATION
1-9
EAS20230
BEARINGS AND OIL SEALS
Install bearings “1”and oil seals “2”so that the
manufacturer marks or numbers are visible.
When installing oil seals “2”, lubricate the oil seal
lips with a light coat of lithium-soap-based
grease. Oil bearings liberally when installing, if
appropriate.
NOTICE
ECA13300
Do not spin the bearing with compressed air
because this will damage the bearing surfac-
es.
EAS20240
CIRCLIPS
Before reassembly, check all circlips carefully
and replace damaged or distorted circlips. Al-
ways replace piston pin clips after one use.
When installing a circlip “1”, make sure the
sharp-edged corner “2”is positioned opposite
the thrust “3”that the circlip receives.

CHECKING THE CONNECTIONS
1-10
EAS20250
CHECKING THE CONNECTIONS
Check the leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
•Lead
•Coupler
•Connector
2. Check:
•Lead
•Coupler
•Connector
Moisture →Dry with an air blower.
Rust/stains →Connect and disconnect sev-
eral times.
3. Check:
•All connections
Loose connection →Connect properly.
T
IP
If the pin “1”on the terminal is flattened, bend it
up.
4. Connect:
•Lead
•Coupler
•Connector
T
IP
Make sure all connections are tight.
5. Check:
•Continuity
(with the pocket tester)
T
IP
•If there is no continuity, clean the terminals.
•When checking the wire harness, perform
steps (1) to (3).
•As a quick remedy, use a contact revitalizer
available at most part stores.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C

SPECIAL TOOLS
1-11
EAS20260
SPECIAL TOOLS
The following special tools are necessary for complete and accurate tune-up and assembly. Use only
the appropriate special tools as this will help prevent damage caused by the use of inappropriate tools
or improvised techniques. Special tools, part numbers or both may differ depending on the country.
When placing an order, refer to the list provided below to avoid any mistakes.
T
IP
•For U.S.A. and Canada, use part number starting with “YM-”, “YU-”, or “ACC-”.
•For others, use part number starting with “90890-”.
Tool name/Tool No. Illustration Reference
pages
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
1-10, 5-38,
8-59, 8-60,
8-61, 8-65,
8-66, 8-67,
8-68, 8-69,
8-70, 8-71,
8-72, 8-73,
8-74
Tappet adjusting tool
90890-01311
Six piece tappet set
YM-A5970
3-5
Timing light
90890-03141
Inductive clamp timing light
YU-03141
3-9
Extension
90890-04082
3-10
Compression gauge
90890-03081
Engine compression tester
YU-33223
3-10
ø9ø8 ø10
ø3 ø4
YM-A5970