Yamaha Mt 01 T 2005 Manual

							ELECTRICAL COMPONENTS
7-106



 





 
 








 
 



 
 



 



a. Disconnect the decompression solenoid cou-
plers from the wire harness.
b. Connect the pocket tester (Ω × 10) to the de-
compression solenoid coupler as shown.
c. Measure the decompression solenoid (ther-
mistor) resistance.
        
2. Check:
Decompression solenoid resistance
Out of specification → Replace.



 





 
 








 
 



 
 



 



a. Connect the pocket tester (Ω × 1) to the de-
compression solenoid coupler as shown.b. Measure the decompression solenoid resis-
tance.
          
EAS28410
CHECKING THE INTAKE AIR PRESSURE 
SENSORS
The following procedure applies to both of the in-
take air pressure sensors.
1. Check:
Intake air pressure sensor output voltage
Out of specification → Replace.



 





 
 



 
 



 
 



 
 



 



a. Connect the pocket tester (DC 20 V) to the in-
take air pressure sensor coupler as shown.
b. Turn the main switch to “ON”.
c. Measure the intake air pressure sensor out-
put voltage.
          
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe →
green “1”
Negative tester probe →
green “2”
 
Decompression solenoid 
resistance
0.96–1.44 Ω at 20 °C (68 °F)
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe →
black “1”
Negative tester probe →
black “2”
 
Intake pressure sensor output 
voltage
2.4 V
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe →
pink/white “1” or pink/yellow
Negative tester probe →
black/blue “2”
LB/LP/W
1 2 
						

							ELECTRICAL COMPONENTS
7-107
ET5YU1007CHECKING THE AIR TEMPERATURE 
SENSOR
1. Remove:
Air temperature sensor
WARNING
EW5YU1002
Handle the air temperature sensor with 
special care.
Never subject the air temperature sensor to 
strong shocks. If the air temperature sen-
sor is dropped, replace it.
2. Check:
Air temperature sensor resistance
Out of specification → Replace.



 





 
 








 
 



 
 



 



a. Connect the pocket tester (Ω × 100) to the air 
temperature sensor terminal as shown.
b. Immerse the air temperature sensor “1” in a 
container filled with water “2”.
NOTE:
Make sure that the air temperature sensor termi-
nals do not get wet.
c. Place a thermometer “3” in the water.
d. Slowly heat the water, then let it cool down to 
the specified temperature.
e. Measure the air temperature sensor resis-
tance.
        
ET5YU1008CHECKING THE INTAKE SOLENOID
1. Check:
Intake solenoid resistance
Out of specification → Replace.



 





 
 



 
 



 
 



 
 



 



a. Disconnect the intake solenoid coupler from 
the intake solenoid.
b. Connect the pocket tester (Ω × 10) to the in-
take solenoid terminal as shown.
c. Measure the intake solenoid resistance.
          
ET5YU1005
CHECKING THE MUFFLER COOLING FAN 
MOTOR
1. Check:
Muffler cooling fan motor
Faulty/rough movement → Replace.



 





 
 



 
 



 
 



 
 



 



a. Disconnect the muffler cooling fan motor cou-
pler from the wire harness.
b. Connect the battery (DC 12 V) as shown.
 
Air temperature sensor 
resistance
290–390 Ω at 80 °C (176 °F)
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
3
1
2
 
Intake solenoid resistance
42–48 Ω at 20 °C (68 °F)
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
brown/black “1”
Negative tester probe
red/white “2”
Positive tester probe →
blue “1”
Negative tester probe →
black “2”
Br/BR/W
1
2 
						

							ELECTRICAL COMPONENTS
7-108
c. Check the muffler cooling fan motor move-
ment.
        
ET5YU1006
CHECKING THE MUFFLER COOLING FAN 
TEMPERATURE SENSOR
1. Remove:
Muffler cooling fan temperature sensor
WARNING
EW5YU1003
Handle the muffler cooling fan temperature 
sensor with special care.
Never subject the intake muffler cooling fan 
temperature sensor to strong shocks. If the 
intake muffler cooling fan temperature sen-
sor is dropped, replace it.
2. Check:
Muffler cooling fan temperature sensor resis-
tance
Out of specification → Replace.



 





 
 








 
 



 
 



 



a. Connect the pocket tester (Ω × 1k) to the muf-
fler cooling fan temperature sensor terminal 
as shown.b. Immerse the muffler cooling fan temperature 
sensor “3” in a container filled with water “4”.
NOTE:
Make sure that the muffler cooling fan tempera-
ture sensor terminals do not get wet.
c. Place a thermometer “5” in the water.
d. Slowly heat the water, then let it cool down to 
the specified temperature.
e. Measure the muffler cooling fan temperature 
sensor resistance.
          
3. Install:
Muffler cooling fan temperature sensor
 
Muffler cooling fan temperature 
sensor resistance
1.82–2.24 kΩ at 75 °C (167 °F)
 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe →
black “1”
Negative tester probe →
black “2”
5
3
4
BB
1
2 
						

							TRBL
SHTG
8 
						

							8
TROUBLESHOOTING
TROUBLESHOOTING..................................................................................... 8-1
GENERAL INFORMATION ....................................................................... 8-1
STARTING FAILURES .............................................................................. 8-1
INCORRECT ENGINE IDLING SPEED .................................................... 8-1
POOR MEDIUM AND HIGH-SPEED PERFORMANCE ........................... 8-2
FAULTY GEAR SHIFTING ........................................................................ 8-2
SHIFT PEDAL DOES NOT MOVE ............................................................ 8-2
JUMPS OUT OF GEAR............................................................................. 8-2
FAULTY CLUTCH ..................................................................................... 8-2
OVERHEATING ........................................................................................ 8-3
POOR BRAKING PERFORMANCE .......................................................... 8-3
FAULTY FRONT FORK LEGS .................................................................. 8-3
UNSTABLE HANDLING ............................................................................ 8-3
FAULTY LIGHTING OR SIGNALING SYSTEM ........................................ 8-3 
						

							TROUBLESHOOTING
8-1
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 trouble-
shooting. Refer to the relative procedure in this 
manual for checks, adjustments, and replace-
ment of parts.
EAS28470STARTING FAILURES
Engine
1. Cylinder(s) and cylinder head(s)
Loose spark plug
Loose cylinder head or cylinder
Damaged cylinder head gasket
Damaged cylinder gasket
Worn or damaged cylinder
Incorrect valve clearance
Improperly sealed valve
Incorrect valve-to-valve-seat contact
Incorrect valve timing
Faulty valve spring
Seized valve
2. Piston(s) and piston ring(s)
Improperly installed piston ring
Damaged, worn or fatigued piston ring
Seized piston ring
Seized or damaged piston
3. Air filter
Improperly installed air filter
Clogged air filter element
4. Crankcase and crankshaft
Improperly assembled crankcase
Seized crankshaft
Fuel system
1. Fuel tank
Empty fuel tank
Clogged fuel tank drain hose
Clogged rollover valve
Clogged rollover valve hose
Deteriorated or contaminated fuel
2. Fuel pump
Faulty fuel pump
Faulty fuel pump relay
3. Throttle body(-ies)
Deteriorated or contaminated fuel
Sucked-in airElectrical system
1. Battery
Discharged battery
Faulty battery
2. Fuse(s)
Blown, damaged or incorrect fuse
Improperly installed fuse
3. Spark plug(s)
Incorrect spark plug gap
Incorrect spark plug heat range
Fouled spark plug
Worn or damaged electrode
Worn or damaged insulator
Faulty spark plug cap
4. Ignition coil(s)
Cracked or broken ignition coil body
Broken or shorted primary or secondary coils
Faulty spark plug lead
5. Ignition system
Faulty ECU
Faulty crankshaft position sensor
Broken generator rotor woodruff key
6. Switches and wiring
Faulty main switch
Faulty engine stop switch
Broken or shorted wiring
Faulty neutral switch
Faulty start switch
Faulty sidestand switch
Faulty clutch switch
Improperly grounded circuit
Loose connections
7. Starting system
Faulty starter motor
Faulty starter relay
Faulty starting circuit cut-off relay
Faulty starter clutch
EAS28490INCORRECT ENGINE IDLING SPEED
Engine
1. Cylinder(s) and cylinder head(s)
Incorrect valve clearance
Damaged valve train components
2. Air filter
Clogged air filter element
Fuel system
1. Throttle body(-ies)
Damaged or loose throttle body joint
Improperly synchronized throttle bodies
Improper throttle cable free play
Flooded throttle body 
						

							TROUBLESHOOTING
8-2
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
Faulty spark plug cap
3. Ignition coil(s)
Broken or shorted primary or secondary coils
Faulty spark plug lead
Cracked or broken ignition coil
4. Ignition system
Faulty ECU
Faulty crankshaft position sensor
Broken generator rotor woodruff key
EAS28510POOR MEDIUM AND HIGH-SPEED 
PERFORMANCE
Refer to “STARTING FAILURES” on page 8-1.
Engine
1. Air filter
Clogged air filter element
Fuel system
1. Fuel pump
Faulty fuel pump
EAS28530FAULTY GEAR SHIFTING
Shifting is difficult
Refer to “Clutch drags”.
EAS28540SHIFT PEDAL DOES NOT MOVE
Shift shaft
Improperly adjusted shift rod
Bent shift shaft
Shift drum and shift forks
Foreign object in a shift drum groove
Seized shift fork
Bent shift fork guide bar
Transmission
Seized transmission gear
Foreign object between transmission gears
Improperly assembled transmission
EAS28550JUMPS OUT OF GEAR
Shift shaft
Incorrect shift pedal position
Improperly returned stopper lever
Shift forks
Worn shift fork
Shift drum
Incorrect axial play
Worn shift drum groove
Transmission
Worn gear dog
EAS28570
FAULTY CLUTCH
Clutch slips
1. Clutch
Improperly assembled clutch
Improperly assembled clutch master cylinder
Improperly assembled clutch release cylinder
Incorrect clutch fluid level
Damaged clutch hose
Loose or fatigued clutch spring
Loose union bolt
Worn friction plate
Worn clutch plate
Damaged clutch release cylinder
2. Engine oil
Incorrect oil level
Incorrect oil viscosity (low)
Deteriorated oil
Clutch drags
1. Clutch
Air in hydraulic clutch system
Unevenly tensioned clutch springs
Warped pressure plate
Bent clutch plate
Swollen friction plate
Bent clutch push rod
Damaged clutch boss
Burnt primary driven gear bushing
Damaged clutch release cylinder
Match marks not aligned
2. Engine oil
Incorrect oil level
Incorrect oil viscosity (high)
Deteriorated oil 
						

							TROUBLESHOOTING
8-3
EAS28590OVERHEATING
Engine
1. Cylinder head(s) and piston(s)
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Fuel system
1. Throttle body(-ies)
Faulty throttle body(-ies)
Damaged or loose throttle body joint
2. Air filter
Clogged air filter element
Chassis
1. Brake(s)
Dragging brake
Electrical system
1. Spark plug(s)
Incorrect spark plug gap
Incorrect spark plug heat range
2. Ignition system
Faulty ECU
EAS28620
POOR BRAKING PERFORMANCE
Worn brake pad
Worn brake disc
Air in hydraulic brake system
Leaking brake fluid
Faulty brake caliper kit
Faulty brake caliper seal
Loose union bolt
Damaged brake hose
Oil or grease on the brake disc
Oil or grease on the brake pad
Incorrect brake fluid level
EAS28660
FAULTY FRONT FORK LEGS
Leaking oil
Bent, damaged or rusty inner tube
Cracked or damaged outer tube
Improperly installed oil seal
Damaged oil seal lip
Incorrect oil level (high)
Cracked or damaged cap bolt O-ringMalfunction
Bent or damaged inner tube
Bent or damaged outer tube
Damaged fork spring
Worn or damaged outer tube bushing
Bent or damaged damper rod
Incorrect oil viscosity
Incorrect oil level
EAS28670
UNSTABLE HANDLING
1. Handlebar
Bent or improperly installed handlebar
2. Steering head components
Improperly installed upper bracket
Improperly installed lower bracket
(improperly tightened ring nut)
Bent steering stem
Damaged ball bearing or bearing race
3. Front fork leg(s)
Uneven oil levels (both front fork legs)
Unevenly tensioned fork spring (both front 
fork legs)
Broken fork spring
Bent or damaged inner tube
Bent or damaged outer tube
4. Swingarm
Worn bearing or bushing
Bent or damaged swingarm
5. Rear shock absorber assembly
Faulty rear shock absorber spring
Leaking oil or gas
6. Tire(s)
Uneven tire pressures (front and rear)
Incorrect tire pressure
Uneven tire wear
7. Wheel(s)
Incorrect wheel balance
Deformed cast wheel
Damaged wheel bearing
Bent or loose wheel axle
Excessive wheel runout
8. Frame
Bent frame
Damaged steering head pipe
Improperly installed bearing race
EAS28710
FAULTY LIGHTING OR SIGNALING SYSTEM
Headlight does not come on
Wrong headlight bulb
Too many electrical accessories
Hard charging 
						

							TROUBLESHOOTING
8-4
Incorrect connection
Improperly grounded circuit
Poor contacts (main or light switch)
Burnt-out headlight bulb
Headlight bulb burnt out
Wrong headlight bulb
Faulty battery
Faulty rectifier/regulator
Improperly grounded circuit
Faulty main switch
Faulty light switch
Headlight bulb life expired
Tail/brake light does not come on
Wrong tail/brake light LED
Too many electrical accessories
Incorrect connection
Burnt-out tail/brake light LED
Tail/brake light LED burnt out
Wrong tail/brake light LED
Faulty battery
Incorrectly adjusted rear brake light switch
Tail/brake light LED life expired
Turn signal does not come on
Faulty turn signal switch
Faulty turn signal/hazard relay
Burnt-out turn signal bulb
Incorrect connection
Damaged or faulty wire harness
Improperly grounded circuit
Faulty battery
Blown, damaged or incorrect fuse
Turn signal flashes slowly
Faulty turn signal/hazard relay
Faulty main switch
Faulty turn signal switch
Incorrect turn signal bulb
Turn signal remains lit
Faulty turn signal/hazard relay
Burnt-out turn signal bulb
Turn signal flashes quickly
Incorrect turn signal bulb
Faulty turn signal/hazard relay
Burnt-out turn signal bulb
Horn does not sound
Improperly adjusted horn
Damaged or faulty hornFaulty main switch
Faulty horn switch
Faulty battery
Blown, damaged or incorrect fuse
Faulty wire harness