YAMAHA YZF-R1SC 2004 Service Manual

8-8
IGNITION SYSTEMELEC
EAS00735
IGNITION SYSTEM
CIRCUIT DIAGRAM
ProCarManuals.com

8-9
IGNITION SYSTEMELEC
1Main switch
4Fuse (main)
6Battery
10Starting circuit cut-off relay
11Neutral switch
12Sidestand switch
14E.C.U.
15Ignition coil #1
16Ignition coil #2
17Ignition coil #3
18Ignition coil #4
19Spark plug
31Crankshaft position sensor
35Cylinder identification sensor
36Lean angle cut-off switch
53Engine stop switch
59Clutch switch
73Fuse (ignition)
ProCarManuals.com

8-10
YESNO 2. Battery

Check the condition of the battery.
Refer to “CHECKING AND CHARGING
THE BATTERY” in chapter 3.
Minimum open-circuit voltage
12.8 V or more at 20C (68F)

Is the battery OK?

Clean the battery
terminals.

Recharge or re-
place the battery.
EAS00739
YESNO
EAS00741
3. Spark plugs
The following procedure applies to all of the
spark plugs.

Check the condition of the spark plug.

Check the spark plug type.

Measure the spark plug gap.
Refer to “CHECKING THE SPARK PLUGS”
in chapter 3.
Standard spark plug
CR9EK (NGK)
Spark plug gap
0.6  0.7 mm (0.0236  0.0276 in)

Is the spark plug in good condition, is it of the
correct type, and is its gap within specifica-
tion?
Re-gap or replace
the spark plug.
IGNITION SYSTEMELEC
NOTE:
YESNO
1. Main and ignition fuses

Check the main and ignition fuses for conti-
nuity.
Refer to “CHECKING THE FUSES” in chap-
ter 3.

Are the main and ignition fuses OK?
Replace the fuse(s).
EAS00737
TROUBLESHOOTING
The ignition system fails to operate (no
spark or intermittent spark).
Check:
1. main and ignition fuses
2. battery
3. spark plugs
4. ignition spark gap
5. ignition coil resistance
6. crankshaft position sensor
7. main switch
8. engine stop switch
9. neutral switch
10. sidestand switch
11. clutch switch
12. starting circuit cut-off relay (diode)
13. lean angle cut-off switch
14. wiring connections
(of the entire ignition system)

Before troubleshooting, remove the following
part(s):
1. seat
2. fuel tank
3. side cowlings

Troubleshoot with the following special tool(s).
Ignition checker
90890-06754
Dynamic spark tester
YM-34487
Pocket tester
90890-03112, YU-3112
EAS00738
ProCarManuals.com

8-11
IGNITION SYSTEMELEC
NOYES
1
a
2
4. Ignition spark gap
The following procedure applies to all of the
spark plugs.

Disconnect the spark plug cap from the
spark plug.

Connect the ignition checker and spark
plug cap as shown.

Set the main switch to “ON”.

Measure the ignition spark gap .

Crank the engine by pushing the starter
switch and gradually increase the spark gap
until a misfire occurs.
Minimum ignition spark gap
6 mm (0.24 in)

Is there a spark and is the spark gap within
specification?
The ignition system
is OK.
5. Ignition coil resistance
The following procedure applies to all of the
ignition coils.

Disconnect the ignition coil leads from the
wire harness.

Connect the pocket tester (Ω
1) to the
ignition coil as shown.
EAS00747
Positive tester probe

ignition coil terminal
Negative tester probe

ignition coil terminal

Connect the pocket tester (Ω
1k) to the
ignition coil as shown.
Measure the primary coil resistance.
Primary coil resistance
1.19  1.61 Ω at 20C
Negative tester probe

ignition coil terminal
Positive tester probe

spark plug terminal
1
2

Measure the secondary coil resistance.
Secondary coil resistance
8.5  11.5 kΩ at 20C

Is the ignition coil OK?
YESNO
Replace the ignition
coil.
EAS00743
ProCarManuals.com

8-12
IGNITION SYSTEMELEC
6. Crankshaft position sensor resistance

Disconnect the crankshaft position sensor
coupler from the wire harness.

Connect the pocket tester (Ω
100) to the
crankshaft position sensor coupler as shown.
Positive tester probe
gray
Negative tester probe
black
1
2

Measure the crankshaft position sensor
resistance.
Crankshaft position sensor
resistance
336  504 Ω at 20C
(between gray and black)

Is the crankshaft position sensor OK?
YESNO
Replace the
crankshaft position
sensor.
EAS00749
7. Main switch

Check the main switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the main switch OK?
YESNO
Replace the main
switch.
EAS00748EAS00750
8. Engine stop switch

Check the engine stop switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the engine stop switch OK?
YESNO
Replace the right
handlebar switch.
EAS00751
9. Neutral switch

Check the neutral switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the neutral switch OK?
YESNO
Replace the neutral
switch.
EAS00752
10. Sidestand switch

Check the sidestand switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the sidestand switch OK?
YESNO
Replace the side-
stand switch.
EAS00763
11. Clutch switch

Check the clutch switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the clutch switch OK?
YESNO
Replace the clutch
switch.
ProCarManuals.com

8-13
IGNITION SYSTEMELEC
12. Starting circuit cut-off relay (diode)

Disconnect the starting circuit cut-off relay
coupler from the wire harness.

Connect the pocket tester (Ω
1) to the
starting circuit cut-off relay coupler as
shown.

Check the starting circuit cut-off relay for
continuity.
Positive tester probe

blue / yellow
Negative tester probe

sky blue
1
2
EAS00753
Positive tester probe

blue / yellow
Negative tester probe

blue / black Continuity
1
3
Positive tester probe

sky blue
Negative tester probe

blue / yellow
2
1
Positive tester probe

blue / black
Negative tester probe

blue / yellow No
continuity
3
1
YESNO
Replace the starting
circuit cut-off relay. When you switch the positive and negative
tester probes, the readings in the above chart
will be reversed.

Are the tester readings correct?
NOTE:
13. Lean angle cut-off switch

Check the lean angle cut-off switch.
Refer to “FUEL INJECTION SYSTEM” in
chapter 7.

Is the lean angle cut-off switch OK?
YESNO
Replace the lean
angle cut-off switch.
EAS00754
14. Wiring

Check the entire ignition system’s wiring.
Refer to “CIRCUIT DIAGRAM”.

Is the ignition system’s wiring properly con-
nected and without defects?
YESNO
Properly connect or
repair the ignition
system’s wiring.
Replace the ECU.
ProCarManuals.com

8-14
1Main switch
4Fuse (main)
6Battery
8Starter relay
9Starter motor
10Starting circuit cut-off relay
11Neutral switch
12Sidestand switch
53Engine stop switch
54Start switch
73Fuse (ignition)
ELECTRIC STARTING SYSTEMELEC
EAS00755
ELECTRIC STARTING SYSTEM
CIRCUIT DIAGRAM
ProCarManuals.com

8-15
ELECTRIC STARTING SYSTEMELEC
EAS00756
STARTING CIRCUIT CUT-OFF SYSTEM
OPERATION
If the engine stop switch is set to “
” and the
main switch is set to “ON” (both switches are
closed), the starter motor can only operate if at
least one of the following conditions is met:

The transmission is in neutral (the neutral
switch is closed).

The clutch lever is pulled to the handlebar (the
clutch switch is closed) and the sidestand is up
(the sidestand switch is closed).
The starting circuit cut-off relay prevents the
starter motor from operating when neither of
these conditions has been met. In this instance,
the starting circuit cut-off relay is open so cur-
rent cannot reach the starter motor. When at
least one of the above conditions has been met
the starting circuit cut-off relay is closed and the
engine can be started by pressing the starter
switch.
WHEN THE TRANSMISSION IS IN
NEUTRAL
WHEN THE SIDESTAND IS UP AND
THE CLUTCH LEVER IS PULLED TO
THE HANDLEBAR
1Battery
2Main fuse
3Main switch
4Ignition fuse
5Engine stop switch
6Starting circuit cut-off relay
7Diode
8Clutch switch
9Sidestand switch
10Neutral switch
11Start switch
12Starter relay
13Starter motor
ProCarManuals.com

8-16
YESNO
3. Starter motor

Connect the positive battery terminal and
starter motor lead with a jumper lead .
Repair or replace the
starter motor.
A wire that is used as a jumper lead
must have at least the same capacity or
more as that of the battery lead, other-
wise the jumper lead may burn.

This check is likely to produce sparks,
therefore make sure nothing flammable
is in the vicinity.

Does the starter motor turn?
WARNING
1
23
EAS00758
YESNO 2. Battery

Check the condition of the battery.
Refer to “CHECKING AND CHARGING
THE BATTERY” in chapter 3.
Minimum open-circuit voltage
12.8 V or more at 20C (68F)

Is the battery OK?

Clean the battery
terminals.

Recharge or re-
place the battery.
EAS00739
ELECTRIC STARTING SYSTEMELEC
NOTE:
YESNO
1. Main and ignition fuses

Check the main and ignition fuses for conti-
nuity.
Refer to “CHECKING THE FUSES” in chap-
ter 3.

Are the main and ignition fuses OK?
Replace the fuse(s).
EAS00757
TROUBLESHOOTING
The starter motor fails to turn.
Check:
1. main and ignition fuses
2. battery
3. starter motor
4. starting circuit cut-off relay
5. starter relay
6. main switch
7. engine stop switch
8. neutral switch
9. sidestand switch
10. clutch switch
11. start switch
12. wiring connections
(of the entire starting system)

Before troubleshooting, remove the following
part(s):
1. seat
2. fuel tank
3. side cowlings
4. throttle body assembly

Troubleshoot with the following special tool(s).
Pocket tester
90890-03112, YU-3112
EAS00738
ProCarManuals.com

8-17
4. Starting circuit cut-off relay

Disconnect the starting circuit cut-off relay
coupler from the wire harness.

Connect the pocket tester (Ω
1) and bat-
tery (12 V) to the starting circuit cut-off relay
coupler as shown.
YESNO
Replace the starting
circuit cut-off relay.
Positive tester probe
blue / white
Negative tester probe
blue / white

Does the starting circuit cut-off relay have
continuity between blue / white and
blue / white ?
1
2
3
4
EAS00759
Positive battery terminal
red / black
Negative battery terminal

black / yellow
EAS00761
5. Starter relay

Disconnect the starter relay coupler from the
coupler.

Connect the pocket tester (Ω
1) and battery
(12 V) to the starter relay coupler as shown.
YESNO
Replace the starter
relay.
Positive battery terminal
blue / white
Negative battery terminal
red / white
Positive tester probe
red
Negative tester probe
black
1
2
3
4

Does the starter relay have continuity be-
tween red and black?
EAS00749
6. Main switch

Check the main switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the main switch OK?
YESNO
Replace the main
switch.
EAS00750
7. Engine stop switch

Check the engine stop switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the engine stop switch OK?
YESNO
Replace the right
handlebar switch.
EAS00751
8. Neutral switch

Check the neutral switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the neutral switch OK?
YESNO
Replace the neutral
switch.
3
4
ELECTRIC STARTING SYSTEMELEC
ProCarManuals.com