Yamaha XV1700P, XV1700PC. Service Manual

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GEN

INFO

FEATURES

FUEL INJECTION SYSTEM
Operation and control

The fuel injection timing, injection duration, ignition timing, and the coil energizing duration are con-
trolled by the ECU. To determine the basic injection timing, the ECU calculates the intake air volume
through the signals from the intake air pressure sensor, throttle position sensor, cylinder identifica-
tion sensor, and crankshaft position sensor.
Furthermore, the ECU calculates the final injection timing by adding the following compensations to
the aforementioned basic injection duration: those obtained from the state of acceleration, as well
as those based on the signals from various sensors such as the engine temperature, intake temper-
ature, atmospheric. At the same time, the ECU assesses the crankshaft position through the signals
from the cylinder identification sensor and the crankshaft position sensor. Then, when the ECU
determines that it is time to inject fuel, it sends an injection command to the injectors. Furthermore,
the ECU also controls the length of time the coil is energized by calculating the ignition timing and
the coil energizing duration based on the signals from these sensors.

Determining the basic injection duration

The intake air volume determines the basic injection duration. In order to operate the engine in an
optimal condition, it is necessary to supply fuel at an air-fuel ratio that corresponds appropriately to
the volume of intake air that is constantly changing, and to ignite it an appropriate timing. The ECU
controls the basic injection duration based on the intake air volume and engine speed data.

Detection of intake air volume

The intake air volume is detected primarily through the signals from the throttle position sensor and
the intake air pressure sensor. The intake air volume is determined in accordance with the signals
from the atmospheric pressure sensor, intake temperature sensor, and the engine speed data.

Composition of basic injection duration

RPM

Injection duration

Cranking

Warm-up

Idle

Acceleration

Constant

Deceleration

Start

After start

Basic injection duration

Voltage compensation duration

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Fuel injection duration during linear control valve operation

The linear control valve supplies air to the intake manifold when starting or during engine warm up.
The intake air volume determines the basic injection duration. As the intake air increases through
the linear control valve, the intake air volume corrects the basic injection duration.
The correction volume changes according to the position of the valve at starting and when the valve
position changes to accommodate the engine temperature and engine oil temperature as the intake
air volume increases.
When the engine oil temperature reaches 80 °C (176 °F) or higher, the linear control valve fully
closes to stop the air volume from increasing and control returns to basic injection control.

Composition of basic injection duration during linear control valve operation

Engine speed (r/min)

Injection duration

Cranking

Warm up

Idling

Acceleration

Fixed

Deceleration

Starting

After starting

Basic injection duration

Voltage compensation duration

Correction volume

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Determining the final injection duration

The intake air volume determines the basic injection duration. However, at a given intake air vol-
ume, the volume of fuel that is required varies by the engine operating conditions such as accelera-
tion or deceleration, or by weather conditions. This system uses various sensors to precisely check
these conditions, applies compensations to the basic injection duration, and determines the final
injection duration based on the operating condition of the engine.

The fuel is cut off under conditions that do not require fuel, in order to stop the injection.

Composition of final injection duration

Injection at start *1

After-start enrichment *2

Warm-up enrichment *3

Acceleration compensation *5

Fuel cut-off Deceleration
compensation *5

Basic injection duration

Voltage compensation duration

RPM

Injection duration

Cranking

Warm-up

Idle

Acceleration

Constant

Deceleration

Start

After start

Intake air pressure

Engine rpm

Degree of

opening of

throttle

Basic injection
quantity

Compensation

Injection
command

Engine

temperature

Intake air

temperature

Atmospheric

pressure

Battery voltage

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FEATURES

Reactive injection duration:
A lag is created between the time the ECU outputs a fuel injection signal to the injector and the time
the injector actually opens. Therefore, the ECU calculates this lag in advance before sending the
actuation signal to the injector. The battery voltage determines the reactive injection duration.
• High voltage

→

short reactive injection duration

• Low voltage

→

long reactive injection duration

LIST OF FUEL INJECTION COMPENSATIONS

Compensation item

Check item

Sensor used

Starting injection *1

Engine temperature

Engine temperature sensor

After-start injection:

After-start enrichment *2

Engine temperature

Engine temperature sensor

Warm-up enrichment *3

Engine temperature

Engine temperature sensor

Intake temperature compensation *4

Intake temperature

Intake temperature sensor

Acceleration compensation/
deceleration compensation *5

Intake air pressure

Intake air pressure sensor

Throttle position

Throttle position sensor

Engine temperature

Engine temperature sensor

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Fuel control during normal driving

In synchronous injection during normal driving, fuel is injected on a cylinder-by-cylinder basis when
all of the conditions below are met:

Other than the stop mode

Cylinder identification completed

Other than overrun

To determine the injection timing, the ECU calculates the injection timing through the use of the 3D
control map provided in the ECU, which is based on the throttle position and the engine speed.
The injection duration is based on the basic injection duration (obtained through the throttle position,
intake air pressure, and engine speed) to which injection duration compensation (based on the sig-
nals from various sensors such as the intake temperature sensor, atmospheric pressure sensor) is
added to determine the final injection duration. As a result, fuel is supplied to the cylinders.
• Normal synchronous injection

Injector #1

Injector #2

Identification of cylinder #1

Identification of cylinder #2

Crankshaft position sensor

Crankshaft identification signal

Injection

Stop

Combustion

Exhaust

Intake

Compression

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• Fuel injection control during normal driving

#1 cylinder fuel injection timing

Basic injection duration

Various types of fuel injection duration compensations

Final injection duration (

)

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Fuel injection compensation control

• Starting injection control
The engine temperature is used for determining the injection duration in order to ensure proper start
ability. To suit the engine’s operating conditions, the starting injection duration is determined by
applying a starting compensation coefficient to the basic injection duration, which forms the basis of
the injection duration.

(Starting injection duration = basic injection duration

injection compensation coefficient)

During starting, injection cylinder control is effected together with injection duration compensation.
The injectors of all cylinders inject only once immediately after receiving a signal from the crankshaft
position sensor during the cranking of the engine. This is called asynchronous injection, in contrast
to the synchronous injection, which is a normal cylinder injection that is effected on a cylinder-by-
cylinder basis.
After the asynchronous injection is completed, and until the ECU receives signals from the cylinder
identification sensor with the engine speed at 400 r/min or higher, the injectors are actuated in pairs
in sync with the signals from the crankshaft position sensor: cylinder #1 and cylinder #2. Controlling
both the injection duration and the injection cylinders in this manner enables a precise supply of fuel
in accordance with the starting conditions of the engine.
• Starting injection duration

Basic injection duration

After-start compensation injection duration

Low

High

Injection duration

Engine temperature

Extended duration

• Starting cylinder control

Injector #1

Injector #2

Starting asynchronous injection

Identification of cylinder #1

Identification of cylinder #2

Crankshaft position sensor

Injection

Stop

Synchronous injection

(˚C)

4 5

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FEATURES

• After-start enrichment
After-start enrichment provides enrichment compensation during a prescribed duration following the
starting (firing) of the engine. While the amount of fuel enrichment is determined by the after-start
enrichment coefficient, the coefficient varies by the engine temperature. Although the engine tem-
perature determines the initial starting enrichment coefficient, the coefficient subsequently changes
in accordance with the damping factor. The enrichment ratio is the highest immediately after the
engine is started, and diminishes gradually. The enrichment of fuel in this manner ensures a stable
engine operation immediately after the engine is started.

Changes in compensation coefficient and compensation injection duration

After-start enrichment

Basic injection
duration

Duration

Long

Short

Injection
duration

Compensation injection
duration

Engine speed

Cranking

Starting enrichment coefficient

Changes in compensation coefficient

Stopped

Initial starting enrichment
coefficient (determined by
engine temperature)

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• Warm-up enrichment
When the engine temperature is low, a warm-up coefficient is applied in accordance with the signals
from the engine temperature sensor in order to effect fuel enrichment. Because the engine temper-
ature determines the coefficient, the coefficient changes with the fluctuations in the engine tempera-
ture. The coefficient increases with the decrease in the engine temperature, and decreases with the
increase in the engine temperature. The ratio of fuel enrichment also changes with the changes in
the coefficient.

Changes in compensation coefficient and compensation injection duration

1.0

(˚C)

Warm-up enrichment

Long

Short

Injection
duration

Compensation injection duration

Duration

Basic injection duration

Low

High

Engine temperature

Changes in compensation coefficient

richme

coef

ficient

all

Lar

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• Acceleration enrichment
Acceleration enrichment is provided in accordance with the signals from the throttle position sensor.
As the rider operates the accelerator to accelerate the motorcycle from a constant speed, the throt-
tle position sensor actuates in unison with the accelerator. The ECU interprets that acceleration has
taken place through the throttle position sensor signal and executes acceleration enrichment. The
enrichment volume is determined by the acceleration enrichment coefficient. The coefficient
increases with the changes in the throttle position sensor, which also increases the actual enrich-
ment volume. The enrichment volume is executed in accordance with the acceleration enrichment
coefficient when the movement of the throttle position sensor has met the acceleration condition as
defined by the ECU. Thereafter, the enrichment volume is regulated by the coefficient that changes
in accordance with the damping rate.

(Acceleration injection duration = basic injection duration

acceleration compensation coef-

ficient)

Changes in compensation coefficient and compensation injection duration

Compensation injection duration

Acceleration enrichment volume

Basic injection duration

Duration

Starting of acceleration

Long

Changes in acceleration

compensation coefficient

Large

Small

Changes in
throttle position
sensor angle

Duration

Starting of acceleration

Injection
duration

Short

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• Deceleration control
Deceleration control is effected in accordance with the signals from the throttle position sensor. As
the rider operates the accelerator to decelerate the motorcycle that is in motion, the throttle position
sensor actuates in unison with the accelerator. When the engine speed is greater than a prescribed
value with the throttle fully closed (thus applying engine braking), the ECU executes a deceleration
fuel cut-off. The injection of fuel to all the cylinders is stopped when fuel cut-off control is executed,
thus improving fuel economy.

Engine speed

Duration

Fuel cut-off control (stopping fuel injection)

Basic injection duration

• Over-revolution control
The over-revolution control of the ECU operates the ignition control and fuel cut-off control when the
engine speed becomes greater than the specified value. The over-revolution control first operates
the ignition control to reduce the ignition of each cylinder to keep the engine speed from rising. If the
engine speed increases after the ignition control is activated, the fuel cut-off control is activated. The
fuel cut-off control is first activated in cylinder #1, then in cylinder #2 as the engine speed increases
further.
In addition, specified engine speeds are set at each gear position, therefore, over-revolution control
can be achieved more accurately.

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FIRST IDLE CONTROL SYSTEM

This system temporarily increases the fuel injection volume of the injectors when starting a cold
engine and until the engine is warm. The system improves startability and stabilizes engine speed
during engine warm up.

Basic operation

The ECU receives a signal from the engine temperature sensor and determines the temperature of
the engine with the collected data. Based on this data, the ECU regulates the linear control valve.
The linear control valve sends air from the silencer air filter case to the intake manifold to increase
the intake air volume. When the engine is started and during engine warm up, the fuel injection vol-
ume is increased to compensate the increase in the air volume.
A signal from the ECU and the temperature of the engine immediately after starting, determine the
air volume introduced by the linear control valve. When the engine is running, the engine oil temper-
ature controls the linear control valve. If the temperature is low, the intake air volume increases. If
the temperature is high, the intake air volume decreases. Furthermore, if the temperature reaches
80

C or higher, the valve fully closes to stop the intake air volume from increasing.

Liner control valve

From silencer air filter case

To intake manifold - cylinder #2

To intake manifold - cylinder #1

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COMPONENTS
Linear control valve

The linear control valve sends air from the silencer box to the intake manifold to increase the intake
air volume.
The linear control valve consists of a stepper motor that operates the valve, a valve unit that is
attached to the motor, and a main body that distributes the intake air. The stepper motor has been
adopted to deduce malfunctions during operation and for high-precision control. The main body
contains air passages, which are opened and closed by the motor, which operates the valve. In
addition, a pipe to introduce air from the silencer air filter case and air pipes to distribute air to each
cylinder are installed on the linear control valve.
The stepper motor used in the XV1700 rotates exactly 15 degrees per step (1 pulse input). With
each step, the valve moves approximately 0.041 mm. The stepper motor is set to make a total of
146 steps, thus the total range of the valve, from fully closed to fully open, is approximately 6.08
mm.
The linear control valve is operated when the engine is started and adjusts its opening to accommo-
date the temperature of the engine. When the engine is started, the control data transfers from the
engine temperature to the engine oil temperature and adjusts the valve opening to accommodate
the engine oil temperature. When the engine oil temperature reaches 80 °C (176 °F) or higher, the
valve fully closes to stop the intake air volume from increasing.
In addition, the linear control valve fully closes when the main switch is turned off, but maintains its
current position if the engine is stopped with the engine stop switch or if the engine stalls. When the
engine is restarted, control starts at the maintained position.

Valve

To intake manifold - cylinder #1

From silencer air filter case

To intake manifold - cylinder #2

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Instrument panel

Function indication
The indications of the self-diagnosis function can be checked and inspection operations can be per-
formed through the use of the tachometer on the instrument panel.
Based on the signals received from the sensors, the ECU inputs the signals into the tachometer.
Then, the conditions of the sensors appear on the clock and trip/odometer display of the tachome-
ter.
1. ECU transmission data and meter display

Note: If the exchange of data between the ECU and the meters is abnormal, the clock LCD shows
error “Er-1~4”. The clock LCD reverts to showing the time after the error has been corrected.

Tachometer

Clock

Odometer/tripmeter/fuel reserve tripmeter

RESET button

SELECT button

Speedometer assembly

Engine trouble warning light

Mode

ECU transmission data

Meter indication

Display description

Common to all

modes

Vehicle speed

Tripmeter

4 digits including decimals

Engine warning

indicator lamp

Indicator lamp

ON/OFF

Self-diagnostic fault

code

Clock LCD

Shows trouble code in numbers

Normal mode

Engine temperature

Indicator lamp

Engine temperature

DIAG mode

Diagnostic code

Clock LCD

Shows diagnostic code in
numbers

Diagnosis sensor value

Trip LCD

Shows data for sensors

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2. DIAG mode inspection and adjustment (multi-function meter)

Clock

Odometer/tripmeter/fuel reserve tripmeter

RESET button

SELECT button

Mode Selection (Make sure to disconnect the coupler from the fuel pump.)

DIAG mode

Normal mode

1. While keeping both the SELECT and

RESET buttons pressed, turn “ON” the
main switch. Keep the buttons pressed for
8 seconds or more.

* All the segments are “OFF” except the

clock and the trip LCD.

* “DIAG” appears on the clock LCD.
2. Simultaneously press the SELECT and

RESET buttons for 2 seconds or more to
select an item.

Turn “ON” the main switch.
* The self-diagnostic function starts a sys-

tem check.

System normal
Normal meter display

Malfunction detection
A fault code number
appears on the clock
LCD.
The engine trouble
warning light illumi-
nates.

(The engine cannot be started in this mode.)
Diagnosis mode
Enables the verification of the operation of the
actuator and various sensors.
* Turn the engine stop switch to “OFF”.

(Turn it “ON” when the diagnostic code is
09 or 03.)

1. Press the SELECT and RESET buttons to

select the Diagnosis mode.

* RESET button = decrement
* SELECT button = increment
* A diagnostic code number appears on the

clock LCD.

2. Checking the operation of the actuator
* Turn “ON” the engine stop switch to start

the operation.

3. Checking the operation of various sensors
* The condition of the operation appears on

the TRIP LCD.

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IMPORTANT INFORMATION

EAS00020

IMPORTANT INFORMATION

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

equipment.
Refer to the “SPECIAL TOOLS”.

3. When disassembling, always keep mated

parts together. This includes gears, cylin-
ders, pistons and other parts that have been
“mated” through normal wear. Mated parts
must always be reused or replaced as an
assembly.

4. During disassembly, clean all of the parts

and place them in trays in the order of dis-
assembly. This will speed up assembly and
allow for the correct installation of all parts.

5. Keep all parts away from any source of fire.

EAS00021

REPLACEMENT PARTS

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 function and
appearance, but inferior in quality.

EAS00022

GASKETS, OIL SEALS AND O-RINGS

1. When overhauling the engine, replace all

gaskets, seals and O-rings. All gasket sur-
faces, 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.

Yamaha XV1700P, XV1700PC. Service Manual - part 3