Yamaha Fz1n Service Manual

ELECTRICAL COMPONENTS
8-107
c. Measure the horn resistance.
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2. Check: Horn soundFaulty sound  → Adjust or replace.
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a. Connect a battery (12 V) to the horn.
b. Turn the adjusting screw in direction “a” or 
“b” until the specified horn sound is 
obtained.
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EAS28230
CHECKING THE FUEL SENDER
1. Remove: Fuel tank
2. Disconnect:
 Fuel pump coupler
 Fuel sender coupler(from the wire harness)
3. Remove:  Fuel pump...

ELECTRICAL COMPONENTS
8-108
b. Set the main switch to “ON”.
c. Elevate the rear wheel and slowly rotate it.
d. Measure the voltage (DC 5 V) of White/Yel-low and Blue. With each full rotation of the 
rear wheel, the voltage reading should 
cycle from 0.6 V to 4.8 V to 0.6 V to 4.8 V.
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EAS28250
CHECKING THE RADIATOR FAN MOTOR
1. Check:
 Radiator fan motorFaulty/rough movement  → Replace.
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a. Disconnect the radiator fan motor coupler 
from the...

ELECTRICAL COMPONENTS
8-109
d. Slowly heat the coolant, and then let it cool to the specified temperature indicated in 
the table.
e. Check the coolant temperature sensor for  continuity at the temperatures indicated in 
the table.
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EAS28300
CHECKING THE THROTTLE POSITION 
SENSOR
1. Remove:
 Throttle position sensor(from the throttle body)
2. Check:  Throttle position sensor
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a. Connect the pocket tester ( Ω ×  1k) to the 
throttle position...

ELECTRICAL COMPONENTS
8-110
NOTE:
When installing the throttle position sensor, 
adjust its angle properly. Refer to ADJUST-
ING THE THROTTLE POSITION SENSOR 
on page 7-8.
EAS2D1010
CHECKING THE SUB-THROTTLE POSITION 
SENSOR
1. Remove: Sub-throttle position sensor(from the throttle body)
2. Check:
 Sub-throttle position sensor
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a. Disconnect the sub-throttle motor coupler.
b. Disconnect the sub-throttle position sensor  coupler.
c. Remove the sub-throttle position sensor...

ELECTRICAL COMPONENTS
8-111
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a. Remove the Air induction system solenoid 
coupler from the wire harness.
b. Connect the pocket tester ( Ω ×  1) to the Air 
induction system solenoid terminal as 
shown.
c. Measure the Air induction system solenoid  resistance.
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EAS28380
CHECKING THE ATMOSPHERIC PRES-
SURE SENSOR
1. Check:
 Atmospheric pressure sensor output volt-age
Out of specification  → Replace.
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a. Connect the...

ELECTRICAL COMPONENTS
8-112
b. Set the main switch to “ON”.
c. Rotate the crankshaft.
d. Measure the voltage (DC 20 V) of White/Black and Black/Blue. With each full rota-
tion of the crankshaft, the voltage reading 
should cycle from 0.8 V to 4.8 V to 0.8 V to 
4.8 V.
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EAS28410
CHECKING THE INTAKE AIR PRESSURE 
SENSOR
1. Check:
 Intake air pressure sensor output voltageOut of specification  → Replace.
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a. Connect the pocket tester (DC 20 V) to...

ELECTRICAL COMPONENTS
8-113 

9
TROUBLESHOOTING
TROUBLESHOOTING.................................................................................. 9-1
GENERAL INFORMATION ..................................................................... 9-1
STARTING FAILURES ............................................................................ 9-1
INCORRECT ENGINE IDLI NG SPEED ................................................. 9-1
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE ........................ 9-2
FAULTY GEAR SHIFTING...

TROUBLESHOOTING
9-1
EAS28450
TROUBLESHOOTING
EAS28460
GENERAL INFORMATION
NOTE:
The following guide for troubleshooting does 
not cover all the possible causes of trouble. It 
should be helpful, however, as a guide to basic 
troubleshooting. Refer to the relative proce-
dure in this manual for checks, adjustments, 
and replacement of parts.
EAS28470
STARTING FAILURES
Engine
1. Cylinder(s) and cylinder head(s) Loose spark plug
 Loose cylinder head or cylinder
 Damaged cylinder head gasket
 Damaged...

TROUBLESHOOTING
9-2
 Improper throttle cable free play
 Flooded throttle body
 Faulty air induction system
Electrical system
1. Battery  Discharged battery
 Faulty battery
2. Spark plug(s)  Incorrect spark plug gap
 Incorrect spark plug heat range
 Fouled spark plug
 Worn or damaged electrode
 Worn or damaged insulator
3. Ignition coil(s)  Broken or shorted primary or secondary coils
 Cracked or broken ignition coil
4. Ignition system Faulty ECU
 Faulty crankshaft position sensor
EAS28510...