YAMAHA YZF-R1SC 2004 Service Manual

7-37
Order Job / Part Q’ty Remarks
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15Removing the injectors
Throttle position sensor coupler
Sub-throttle position sensor coupler
Sub-throttle motor assembly coupler
Intake air pressure sensor coupler
Cylinder #1-injector coupler
Cylinder #2-injector coupler
Cylinder #3-injector coupler
Cylinder #4-injector coupler
Sub wire harness
Negative pressure hose
Intake air pressure sensor
Fuel distributor
Injector
Spring
Thermo wax assembly1
1
1
1
1
1
1
1
1
1
1
1
4
1
1Remove the parts in the order listed.
Disconnect.
Disconnect.
Disconnect.
Disconnect.
Disconnect.
Disconnect.
Disconnect.
Disconnect.
THROTTLE BODIESFI
INJECTORS
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7-38
THROTTLE BODIESFI
Order Job / Part Q’ty Remarks
16
17
18
19
20
21
22
23Idle adjust screw wire
Cotter pin
Washer
Link
Sub-throttle servo motor assembly
Throttle position sensor
Fuel pressure regulator
Throttle body assembly1
2
2
1
1
1
1
1
For installation, reverse the removal
procedure.
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7-39
THROTTLE BODIESFI
CAUTION:
EAS00911
The throttle bodies should not be disas-
sembled.
EAS00912
CHECKING THE INJECTORS
1. Check:

injectors
Damage
Replace.
EAS00913
CHECKING THE THROTTLE BODIES
1. Check:

throttle bodies
Cracks / damage
Replace the throttle bo-
dies as a set.
2. Check:

fuel passages
Obstructions
Clean.
a. Wash the throttle bodies in a petroleum-
based solvent.
Do not use any caustic carburetor cleaning
solution.
b. Blow out all of the passages with com-
pressed air.
EAS00095
CHECKING THE THROTTLE BODY JOINTS
The following procedure applies to all of the
throttle body joints and intake manifolds.
1. Remove:

throttle bodies
Refer to “THROTTLE BODIES”.
2. Check:

throttle body joints
1
Cracks / damage
Replace.
3. Install:

throttle bodies
Refer to “THROTTLE BODIES”.
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7-40
THROTTLE BODIESFI
NOTE: CHECKING THE PRESSURE REGULATOR
1. Check:

pressure regulator
Damage
Replace.
CHECKING THE FUEL PUMP AND
PRESSURE REGULATOR OPERATION
1. Check:

pressure regulator operation
a. Remove the fuel tank.
Refer to “FUEL TANK” in chapter 3.
b. Disconnect the negative pressure hose
1
from the pressure regulator at the joint.
c. Connect the vacuum / pressure pump gauge
set
2 onto the negative pressure hose from
the pressure regulator.
d. Connect the pressure gauge
3 and adapter
4 onto the fuel injection pipe.
Vacuum / pressure pump gauge set
90890-06756, YB-35956
Pressure gauge
90890-03153, YU-03153
Adapter
90890-03176, YM-03176
e. Install the fuel tank.
Refer to “FUEL TANK” in chapter 3.
f. Start the engine.
g. Measure the fuel pressure.
Fuel pressure
294 kPa (2.94 kg / cm
2, 42.6 psi)
h. Use the vacuum pressure pump gauge set to
adjust the fuel pressure in relation to the vac-
uum pressure as described below.
The vacuum pressure should not exceed 100
kPa (760 mmHg, 29.9 inHg).
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7-41
THROTTLE BODIESFI
NOTE:
Increase the vacuum pressure

Fuel pressure is decreased
Decrease the vacuum pressure

Fuel pressure is increased
Faulty
Replace the pressure regulator.
EAS00916
CHECKING AND ADJUSTING THE
THROTTLE POSITION SENSOR
Before adjusting the throttle position sensor, the
engine idling speed should be properly ad-
justed.
1. Check:

throttle position sensor
a. Disconnect the throttle position sensor cou-
pler.
b. Remove the throttle position sensor from the
throttle body.
c. Connect the pocket tester (Ω  1k) to the
throttle position sensor.
Positive tester probe
blue terminal
1
Negative tester probe

black / blue terminal
2
d. Measure the maximum throttle position sen-
sor resistance.
Out of specification
Replace the throttle
position sensor.
Maximum throttle position
sensor resistance
4
6 kΩ at 20C (68F)
(blue – black / blue)
e. Connect the pocket tester (Ω  1k) to the
throttle position sensor.
Positive tester probe
yellow terminal
3
Negative tester probe

black / blue terminal
2
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7-42
THROTTLE BODIESFI
NOTE:
Tester positive probe

yellow terminal
Tester negative probe

black / blue terminal
1
2
f. While slowly opening the throttle, check that
the throttle position sensor resistance is with-
in the specified range.
The resistance does not change or it
changes abruptly
Replace the throttle
position sensor.
The slot is worn or broken
Replace the
throttle position sensor.
Check mainly that the resistance changes grad-
ually when turning the throttle, since the read-
ings (from closed to wide-open throttle) may dif-
fer slightly from those specified.
Throttle position sensor
resistance
0
6 kΩ at 20C (68F)
(yellow – black)
2. Adjust:

throttle position sensor angle
a. Connect the throttle position sensor coupler
to the wire harness.
b. Connect the digital circuit tester to the throttle
position sensor.
Digital circuit tester
90890-03174
c. Measure the throttle position sensor voltage.
d. Adjust the throttle position sensor angle so
the measured voltage is within the specified
range.
Throttle position sensor voltage
0.63
0.73 V
(yellow – black / blue)
e. After adjusting the throttle position sensor
angle, tighten the throttle position sensor
screws.
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7-43
THROTTLE BODIESFI
NOTE:
CHECKING AND ADJUSTING THE
SUB-THROTTLE POSITION SENSOR
1. Check:

sub-throttle position sensor
a. Disconnect the sub-throttle position sensor
coupler.
b. Remove the sub-throttle position sensor
from the sub-throttle servo motor.
c. Connect the pocket tester (Ω  1k) to the
sub-throttle position sensor.
Positive tester probe
blue terminal
1
Negative tester probe

black / blue terminal
2
d. Measure the maximum sub-throttle position
sensor resistance.
Out of specification
Replace the sub-
throttle position sensor.
Maximum sub-throttle position
sensor resistance
4
6 kΩ at 20C (68F)
(blue – black / blue)
e. Connect the pocket tester (Ω  1k) to the
sub-throttle position sensor.
Positive tester probe

green / yellow terminal
3
Negative tester probe

black / blue terminal
2
f. While slowly opening the sub-throttle worm
nut, check that the sub-throttle position sen-
sor resistance is within the specified range.
The resistance does not change or it changes
abruptly
Replace the sub-throttle position
sensor.
Check mainly that the resistance changes grad-
ually when turning the sub-throttle worm nut,
since the readings (from closed to wide-open
sub-throttle) may differ slightly from those spe-
cified.
Sub-throttle position sensor
resistance
0
6 kΩ at 20C (68F)
(black / blue – green / yellow)
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7-44
THROTTLE BODIESFI
2. Adjust:

sub-throttle position sensor full open angle
a. Turn the nut
1 of the worm shaft of the sub-
throttle counterclockwise until it contacts
with the full open stopper.
b. When the dimension of
a sections of the
throttle bodies #3 and #4 is measured with a
micrometer caliper, adjust with the adjuster
2 of the output shaft section of the sub-
throttle servo motor so that the dimension is
in a range from 24.2 to 24.6 mm (0.95 to 0.97
in).
AFront side
BRear side
Sub-throttle dimension a
24.2
24.6 mm (0.95
0.97 in)
c. After adjusting the dimension of
a sections
of the throttle bodies #3 and #4, measure the
dimension of
a sections of #1 and #2.
d. If the dimension of
a sections of the throttle
bodies #1 and #2 is different from the dimen-
sion of
a sections of the throttle bodies #3
and #4, adjust it to the same dimension as
the measurement value adjusted for the
throttle bodies #3 and #4, using the tuning
screw
3 located between the throttle bodies
#2 and #3.
3. Adjust:

primary opening
a. After performing the full open angle of the
sub-throttle position sensor, turn the nut of
the worm shaft clockwise, measure the di-
mension of
b section with a micrometer cali-
per or other device and adjust so that the di-
mension is in a range from 8.1 to 8.5 mm
(0.32 to 0.33 in).
AFront side
BRear side
Sub-throttle dimension b
8.1
8.5 mm (0.32
0.33 in)
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7-45
A
THROTTLE BODIESFI
NOTE:
NOTE:
b. After performing the step a, move the sub-
throttle position sensor to adjust to be in a
range from 0.97 to 1.07 V
Sub-throttle position sensor
voltage
0.97
1.07 V
(green / yellow – blue)

After setting up the sub-throttle position sen-
sor, check that the sub-throttle position sensor
output voltage is 0.4 V or more with the nut of
worm shaft turned to the full close side until it
stops.

When the sub-throttle position sensor output
voltage is 0.4 V or more, check that the sub-
throttle position sensor output voltage is 4.6 V
or less with the nut of worm shaft turned to the
full open side until it stops.
CHECKING AND ADJUSTING THE THERMO
WA X
1. Check:

thermo wax
1
Damege
Replace the thermo wax.
2. Adjust:

thermo wax the end face distance
a
a. Before adjusting the distance, push the rod
b in order to be fitted in several times by
hand.
b. Measure the outside air temperature, and
adjust the distance
a by turning the adjust-
ing screw
2. Refer to the thermo wax toler-
ance table based on the measured outside
air temperature for correct adjustment.

Setup tolerance of the longitudinal axis should
be  0.2 mm ( 0.008 in).

After adjusting the thermo wax, check that the
first idling is released at the coolant tempera-
ture around 60C (140F) by idling.

If the first idling is not released around 60C
(140F), make sure to set it again. (When the
coolant temperature is low, adjust the distance
between the end faces longer or adjust it short-
er when the coolant temperature is high.)

In case of turning the adjusting bolt two-third
turn, the temperature varies about 10C
(50F).
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7-46
AIR INDUCTION SYSTEMFI
EAS00507
AIR INDUCTION SYSTEM
AIR INJECTION
The air induction system burns unburned ex-
haust gases by injecting fresh air (secondary
air) into the exhaust port, reducing the emission
of hydrocarbons.
When there is negative pressure at the exhaust
port, the reed valve opens, allowing secondary
air to flow into the exhaust port. The required
temperature for burning the unburned exhaust
gases is approximately 600 to 700C (1112 to
1292F).
EAS0097
AIR CUT-OFF VALVE
The air cut-off valve is controlled by the signals
from the ECU in accordance with the combus-
tion conditions. Ordinarily, the air cut-off valve
opens to allow the air to flow during idle and
closes to cut-off the flow when the motorcycle is
being driven. However, if the coolant tempera-
ture is below the specified value, the air cut-off
valve remains open and allows the air to flow
into the exhaust pipe until the temperature be-
comes higher than the specified value.
AFrom the air cleaner
BTo the cylinder head
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