Yamaha XV1700P, XV1700PC. Service Manual - part 2

 

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Yamaha XV1700P, XV1700PC. Service Manual - part 2

 

 

1 - 1

GEN

INFO

EAS00014

GENERAL INFORMATION 

MOTORCYCLE IDENTIFICATION

EAS00017

VEHICLE IDENTIFICATION NUMBER

The vehicle identification number 

1

 is

stamped into the right side of the steering head
pipe.

EAS00018

MODEL LABEL

The model label 

1

 is affixed to the frame. This

information will be needed to order spare
parts.

MOTORCYCLE IDENTIFICATION

1

1 - 2

GEN

INFO

FEATURES

FEATURES

OUTLINE

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 com-
bustion 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 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. 

1

Liner control valve

2

Intake air pressure sensor 2

3

Intake air temperature sensor

4

Intake air pressure sensor 1

5

Engine temperature sensor

6

Atmospheric pressure sensor

7

Throttle position sensor

8

Spark plug

9

Relay unit

0

ECU

A

Battery

B

Fuel pump

C

Lean angle cut-off switch

D

Oil temperature sensor

E

Decompression solenoid

F

Crankshaft position sensor

G

Cylinder identification sensor

H

Ignition coil 

3

2

1

H G

8 F E D

C

B

A

0

9

8

7

5

4

6

1 - 3

GEN

INFO

FEATURES

FI SYSTEM

The fuel pump delivers fuel to the injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the injector at only 2.55 kg/cm

2

 higher than the intake manifold pres-

sure. Accordingly, when the energizing signal from the ECU energizes the 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 injector is energized (injection duration),
the greater the volume of fuel that is supplied. Conversely, the shorter the length of time the 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, atmospheric
pressure sensor, intake temperature sensor, engine temperature sensor, and oil temperature sen-
sor enable the ECU to determine the injection duration. The injection timing is determined through
the signals from the crankshaft position sensor and the cylinder identification 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.

1

Fuel pump

2

Pressure regulator

3

Fuel injector

4

Throttle body

5

Intake temperature sensor

6

Throttle position sensor

7

Intake air pressure sensor

8

ECU

9

Atmospheric pressure sensor

0

Engine temperature sensor

A

Cylinder identification sensor

B

Crankshaft position sensor

È

Fuel system

É

Air system

Ê

Control system

#2 #1

È

Ê

É

1

9

7

5

8

B

0

6

4

3

A

2

Illustration is for reference only.

1 - 4

GEN

INFO

FEATURES

Fuel control block

The fuel control block consists of the following main components:

An FI warning light is provided on meter panel.

Component

Function 

Control block

ECU

Total FI system control

Throttle body

Air volume control

Pressure regulator

Fuel pressure adjustment

Sensor block

Intake air pressure sensor

Intake air pressure detection

Atmospheric pressure sensor

Atmospheric pressure detection

Engine temperature sensor

Engine temperature detection

Intake temperature sensor

Intake temperature detection

Throttle position sensor

Throttle angle detection

Oil temperature sensor

Engine oil temperature detection

Cylinder identification sensor

Reference position detection

Crankshaft position sensor

Crankshaft position detection and engine
RPM detection

Speed sensor

Speed detection

Actuator block

Injector

Fuel injection

Fuel pump

Fuel feed

Air Induction system, air cut valve

Induction of secondary air

Liner control valve

First idle control (see page 1-28)

1 - 5

GEN

INFO

FEATURES

COMPONENTS
ECU (Electronic Control Unit)

The ECU is mounted underneath the seat, above the battery box. The main functions of the ECU
are ignition control, fuel control, self-diagnosis, and load control.

• ECU’s internal construction and functions

The main components and functions of the ECU can be broadly divided into the following four
items:
A. Power supply circuit

The power supply circuit obtains power from the battery (12 V) to supply the power (more than
5 V) that is required for operating the ECU.

B. Input interface circuits

The input interface circuits convert the signals output by all the sensors into digital signals,
which can be processed by the CPU, and input them into the CPU.

C. CPU (Central Processing Unit)

The CPU determines the condition of the sensors in accordance with the level of the signal that
is output by the respective sensor. Then, the signals are temporarily stored on the RAM in the
CPU. Based on those stored signals and the basic processing program on the ROM, the CPU
calculates the fuel injection duration, injection timing, and ignition timing, and then sends con-
trol commands to the respective output interface circuits.

D. Output interface circuits

The output interface circuits convert the control signals output by the CPU into actuating sig-
nals for the respective actuators in order to actuate them. They also output commands to the
indicator and relay output circuits as needed.

Battery

Power 
supply 

circuit

ECU

Output 

interface circuit

Input 

interface circuit

CPU

RAM/ROM

MEMORY

Waveform 

shaping circuit

Waveform 

shaping circuit

Digital input circuit

A/D converter 

input circuit

Injector drive
output circuit

Ignition output circuit

Lamp drive

output circuit

Relay drive

output circuit

Hall sensor

signal

(for cylinder

identification)

Pickup coil signal

(for identifying the

crankshaft position)

Switches

Sensors

Injector

Ignition coil

Indicating lamp

Relay

1 - 6

GEN

INFO

FEATURES

• Ignition control

The ignition timing control uses the signals from the throttle position sensor (to detect the angle of
the throttle), and the crankshaft position sensor (to detect the speed of the engine) and the speed
sensor. This control establishes an ignition timing that suits the operating condition of the engine
through compensations made to the basic ignition timing control map. The ignition energizing
duration control establishes the energizing duration to suit the operating conditions by calculating
the energizing duration in accordance with the signal received from the crankshaft position sensor
and the battery voltage.

• Fuel control

The fuel control function of the ECU controls the injection timing and injection duration. The injec-
tion timing control controls the injection timing during the starting of the engine and the injection
timing during the normal operation of the engine, based on the signals received from the crank-
shaft position sensor and the cylinder identification sensor. The injection duration control deter-
mines the duration of injection based on the signals received from the atmospheric pressure
sensors, temperature sensors, and the position sensors, to which compensations are made to suit
various conditions such as the weather, atmospheric pressure, starting, acceleration, and deceler-
ation.

• Load control

The ECU effects load control in the following manner:
1. Stopping the fuel pump and injectors when the motorcycle overturns

The ECU turns OFF the fuel injection system relay when the lean angle cut-off switch is tripped.

2. Operating the headlight illumination relay

The ECU controls the headlight relay in accordance with the engine speed as required by the
daytime illumination specification.

3. Operating the liner control valve

The ECU controls the liner control valve to increase the intake air volume for starting the engine
under cold conditions.

4. Operating the automatic decompression solenoid valve

The ECU controls the operation of the automatic decompression solenoid valve when the
engine is started.

1 - 7

GEN

INFO

FEATURES

• Self-diagnosis function

The ECU is equipped with a self-diagnosis function to ensure that the engine control system is
operating normally. The ECU mode functions include a diagnosis mode in addition to the normal
mode.
Normal mode
• To check for any blown bulbs, this mode illuminates a warning light while the main switch is

turned ON, and while the starter switch is being pressed.

• If the starting disable warning is activated, this mode alerts the rider by blinking the warning light

while the start switch is being pressed.

• If a malfunction occurs in the system, this mode provides an appropriate substitute characteristic

operation, and alerts the rider of the malfunction by illuminating a warning light. After the engine
is stopped, this mode displays a fault code on the clock LCD.

Diagnosis mode
• In this mode, a diagnostic code is input into the ECU through the operation of the operating

switch on the meter, and the ECU displays the values output by the sensors or actuates the
actuators in accordance with the diagnostic code. Whether the system is operating normally can
be checked by observing the illumination of the warning light, the values displayed on the meter,
or the actuating state of the actuators.

1 - 8

GEN

INFO

FEATURES

Fuel pump

The fuel pump, which is mounted in the fuel tank, draws the fuel directly from the tank and pumps it
to the injector.
A filter that is provided in the fuel pump prevents any debris in the fuel tank from entering the fuel
system downstream of the pump.
The pump consists of a pump unit, electric motor, filter, and valves.
The pump unit is a Wesco type rotary pump that is connected to the motor shaft.
A relief valve is provided to prevent the fuel pressure from rising abnormally if the fuel hose
becomes clogged. This valve opens when the fuel pressure at the discharge outlet reaches
between 440 and 640 kpa, and returns the fuel to the fuel tank.

1

Fuel filter

2

Fuel inlet strainer

3

Fuel inlet

4

Fuel outlet

5

Air vent pipe

È

From main fuel tank

É

To injectors

Ê

To main fuel tank

1

5

4

3

5

4

3

2

1

È

É

Ê

1 - 9

GEN

INFO

FEATURES

Pressure regulator

It regulates the fuel pressure that is applied to the injectors that supply fuel to the cylinders in order
to maintain a constant pressure.
The fuel that is delivered by the fuel pump fills the fuel chamber through the fuel inlet of the regulator
and exerts pressure on the diaphragm in the direction for opening the valve.
A spring that is provided in the spring chamber exerts pressure on the diaphragm in the direction for
closing the valve, in contrast to the pressure of the fuel. Thus, the valve cannot open unless the fuel
pressure overcomes the spring force.
By the atmospheric pressure applied to the spring chamber and when the fuel pressure exceeds the
sum of the atmospheric pressure and spring force, the diaphragm opens the valve, allowing fuel to
return to the fuel tank from the return hose.
Therefore, the fuel pressure applied to the injectors by the pressure regulator is controlled by the
atmospheric pressure and the spring force to maintain the fuel pressure in accordance to the
changes of the atmospheric pressure.

1

Spring chamber

2

Spring

3

Diaphragm

4

Fuel inlet

5

Fuel outlet

6

Fuel chamber

7

Valve

8

Atmospheric pressure 
sensor

È

Spring pressure

É

Fuel pressure

È

É

1

2

3

4

6

7

8

5

1 - 10

GEN

INFO

FEATURES

Fuel injector

Upon receiving injection signals from the ECU, the fuel injector injects fuel. In the normal state, the
core is pressed downward by the force of the spring, as illustrated. The needle that is integrated
with the bottom of the core keeps the fuel passage closed.
When the current flows to the coil in accordance with the signal from the ECU, the core is drawn
upward, allowing the flange that is integrated with the needle to move to the spacer. Since the dis-
tance of the movement of the needle is thus kept constant, the opening area of the fuel passage
also becomes constant. Because the pressure difference of the fuel to the intake manifold pressure
is kept constant by the pressure regulator, the fuel volume varies in proportion to the length of time
the coil is energized. The injector that has been recently adopted has a four-hole type injection ori-
fice that enhances the atomization of fuel and improves combustion efficiency.

1

Fuel

2

Coil

3

Core

4

Spacer

5

Needle

6

Inject

7

Flange

2

3

4

5

6

7

1

1 - 11

GEN

INFO

FEATURES

Crankshaft position sensor

The crankshaft position sensor uses the signals of the crankshaft position sensor that is mounted on
the left side of the crankshaft. When the rotation of the pickup rotor that is attached to the crankshaft
causes the projections on the rotor to pass by the crankshaft position sensor, an electromotive force
is generated in the coil. The voltage of this force is then input into the ECU, which calculates the
position of the crankshaft and the speed of the engine. The ignition timing is then determined in
accordance with the calculated data, in order to determine the corresponding injection timing.
Based on the changes in the time intervals of the signals generated by the crankshaft position sen-
sor, the ECU calculates the ignition timing advance to suit the operating conditions. The injection
timing is also advanced in accordance with the ignition timing in order to supply fuel to the engine at
an optimal timing.

1

Pickup rotor

2

Identification of cylinder #1 (82° BTDC)

3

Ignition of cylinder #1 (10° BTDC)

4

Identification of cylinder #2

5

Ignition of cylinder #2

È

Direction of rotation

É

Compression stroke of cylinder #1 (10° BTDC)

Ê

Crankshaft position sensor

Ë

Compression

Ì

Combustion

Í

Exhaust

Î

Intake

H

IT

I

5PX-00

É

È

Ê

Ë

Ì

Í

Î

Ë

Ì

Í

Í

Î

Ë

Ì

Í

Î

4

5

1

2 3

#1

#2

10˚

1 - 12

GEN

INFO

FEATURES

Cylinder identification sensor

The cylinder identification sensor is installed on the camshaft drive gear cover. When the cam of cyl-
inder #1 rotates, the pickup rotor installed on the cam also rotates. When the pickup rotor passes by
the sensor, trigger poles on the rotor generate a signal and send it to the ECU. Based on this signal
and the signal from the crankshaft position sensor, the ECU then actuates the injectors to supply
fuel.

Cylinder identification

When the crank angle is 110 degrees or higher, no signals are transmitted from the crankshaft posi-
tion sensor to the ECU. Once the crank angle is less than 110 degrees, the first signal that the ECU
receives from the sensor identifies cylinder #1 at 82

°

 BTDC. When the ECU receives a signal from

the cylinder identification sensor, cylinder #1 is at 82

°

 BTDC on the exhaust stroke. When the ECU

does not receive a signal from the cylinder identification sensor, cylinder #1 is at 82

°

 BTDC on the

compression stroke.

1

Front cylinder camshaft

2

Front cylinder camshaft end cover

3

Cylinder identification sensor

4

Exhaust stroke of cylinder #1 (82° BTDC)

5

Compression stroke of cylinder #1 (82° BTDC)

È

Crankshaft position sensor signal

É

Cylinder identification sensor signal

Ê

Compression

Ë

Combustion

Ì

Exhaust

Í

Intake

È

É

Ë

Ì

Í

Ê

Ë

Ì

Í

Í

Ê

Ì

Ê

Ë

Ì

Í

Ê

Ë

4

5

1

#1

#2

2

3

1 - 13

GEN

INFO

FEATURES

Throttle position sensor

The throttle position sensor measures the intake air volume by detecting the position of the throttle
valve. It detects the mechanical angle of the throttle valve through the positional relationship
between the moving contact that moves in unison with the throttle shaft and the resistor board. In
actual operation, the ECU supplies 5 V power to both ends of the resistor board and the voltage that
is output by the throttle position sensor is used to determine the angle of the throttle valve.

1

Moving contact

2

Resistor board

3

Spring

È

Output voltage

É

Idling output position

Ê

Full close

Ë

Full open

5.0

4.0

3.0

2.0

1.0

0.68 V

3.88

17˚

97˚

È

É

Ê

Ë

3

2

1

1 - 14

GEN

INFO

FEATURES

Intake air pressure sensor and atmospheric pressure sensor

• Intake air pressure sensor

The intake air pressure sensor is used for measuring the intake air volume. The intake air volume of
every intake stroke is proportionate to the intake air pressure. Therefore, the intake air volume can be
measured by measuring the intake air pressure. The intake air pressure sensor converts the mea-
sured intake air pressure into electrical signals and sends those signals to the ECU. When the intake
air pressure is introduced into the sensor unit, which contains a vacuum chamber on one side of the
silicon diaphragm, the silicon chip that is mounted on the silicon diaphragm converts the intake air
pressure into electrical signals. Then, an integrated circuit (IC) amplifies and adjusts the signals and
makes temperature compensations, in order to generate electrical signals that are proportionate to
the pressure.

• Atmospheric pressure sensor

The atmospheric pressure sensor is used for making compensations to the changes in the air
density caused by the changes in the atmospheric pressure (particularly at high altitudes). The
operating principle and function of the atmospheric pressure sensor are the same as those of the
aforementioned intake air pressure sensor.

1

EMI shield

2

Sensor unit

3

Through condenser

4

Hybrid IC

5

Cap

6

Silicon diaphragm

7

Vacuum chamber

8

Solder

9

Silicon chip

0

Gold wire

A

Lead pin

B

Stem

C

Pressure induction pipe

D

Atmospheric pressure,
intake air pressure

È

Output voltage

É

Input pressure

(V)

4.00

1.842

0.789

È

É

P

20

46

101

1

2

3

4

5

6

7

8

9

0

A

B

C

D

1 - 15

GEN

INFO

FEATURES

Engine temperature sensor

The signals from the engine temperature sensor are used primarily for making fuel volume compen-
sations during starting and warm-up. The engine temperature sensor converts the temperature of
the engine into electrical signals and sends them to the ECU.

1

Connector

2

Terminal

3

Tube

4

Thermistor

5

Holder

È

Resistance k

É

Temperature °C (°F)

Intake temperature sensor

The intake temperature sensor corrects the deviation of the air-fuel mixture that is associated with
the changes in the intake air density, which are created by the changes in the intake air temperature
that occur due to atmospheric temperatures. This sensor uses a semi-conductor thermistor that has
a large resistance at low temperatures and a small resistance at high temperatures. The thermistor
converts the temperature-dependent changes in resistance into electrical resistance values, which
are then input into the ECU.

1

Connector

2

Terminal

3

Tube

4

Thermistor

5

Holder

È

Resistance k

É

Temperature °C (°F)

È

É

100(212)

0.99

10.0

67.0

2

3

1

4

5

-20(-4)

0(32)

20(68)

40(104) 60(140)

-20(-4)

0(32)

20(68)

40(104) 60(140) 80(212)

0.34

6.0

È

É

1

2

3

4

5

1 - 16

GEN

INFO

FEATURES

Lean angle cut-off switch

The lean angle cut-off switch stops the supply of fuel to the engine in case the motorcycle overturns.
When the motorcycle is in the normal state, the cut-off switch outputs a constant voltage of approxi-
mately 1.0 V (low level). When the motorcycle tilts, the float in the switch tilts in proportion to the tilt
of the motorcycle. However, the voltage output to the ECU remains unchanged at the low level.
When the tilt of the motorcycle exceeds 70 degrees (according to the tilt of the float), the signal from
the sensor increases to approximately 4.0 V (high level). When the ECU receives the high-level volt-
age, it determines that the motorcycle has overturned, and stops the delivery of fuel to the engine by
turning OFF the fuel injection system relay that powers the fuel pump and the injectors. Once the
cut-off switch is tripped, the ECU maintains this state; therefore, even if the motorcycle has recov-
ered its upright position, this state will not be canceled unless the main switch is turned OFF, and
then turned back ON.

1

Shaft

2

Float

3

Magneto

4

IC unit

È

Output voltage

É

High level

Ê

Low level

Ë

Cut-off switch tilt angle

Ì

Fuel injection system relay OFF

65

˚

65

˚

20˚ 40˚ 60˚

80˚

65˚

1.0

4.0

V

È

É

Ê

Ë

Ì

ON

ON

1

2

3

4

 

 

 

 

 

 

 

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