YAMAHA TT600RE 2004 Service Manual

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FAILURE TO START/
DIFFICULTIES IN STARTING
8-1
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TROUBLESHOOTING
NOTE:
The troubleshooting tables that follow do not identify every cause of trouble. They may however prove
helpful as a guide to identifying trouble. To inspect, adjust or replace parts, refer to the appropriate sec-
tion in the manual.
FAILURE TO START/DIFFICULTIES IN STARTING
FUEL SYSTEM
Fuel tank
Fuel cock
Carburetor
Air filter PROBABLE CAUSES
•Empty
•Fuel filter obstructed
•Fuel tank air cap passage obstructed
•Petrol contains water or impurities or is adulterated
•Hose obstructed
•Fuel filter obstructed
•Petrol contains water or impurities or is adulterated
•Pilot jet obstructed
•Pilot air passage obstructed
•Infiltrations of air
•Deformation of float
•Needle valve worn or scratched
•Needle valve seat insufficiently sealed
•Fuel level set wrongly
•Pilot jet set wrongly
•Starter jet obstructed
•Malfunctioning of the starter piston
•Air filter element obstructed
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FAILURE TO START/
DIFFICULTIES IN STARTING
8-2
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Spark plug
Ignition coil
Ignition unit
Switches and cables PROBABLE CAUSES•Electrodes gap not correct
•Electrodes worn
•Feed cable interrupted
•Wrong thermal grading of spark plug
•Defective spark plug cap
•Primary or secondary winding interrupted
•High voltage cable defective
•Defective coil
•Defective unit
•Defective pick-up coil
•Woodruff key broken
Starter motor
•Starter motor defective
•Starter motor relay defective
•Diodes defectives
•Starter one-way bearing defective
•Main switch defective
•Emergency stop engine switch defective
•Harness with cable interrupted
•Neutral switch defective
•Sidestand switch defective
•Clutch switch defective
•Starter switch defective
ELECTRICAL SYSTEM
Cylinder and cylinder head
Piston and piston rings
Crankcase and valves, crankshaft PROBABLE CAUSES
•Spark plug tightening insufficiently
•Cylinder head or cylinder insufficiently tightened
•Cylinder head gasket broken
•Cylinder gasket broken
•Cylinder worn, damaged or seized
•Piston rings wrongly assembled
•Piston rings worn, yielded or broken
•Piston rings stuck together
•Piston seized or damaged
•Poor crankcase sealing
•Crankshaft oil seal edge damaged
•Poor valve sealing
•Valve and seat with insufficient contact
•Valve timing wrongly
•Valve spring broken
•Crankshaft seized
•Camshaft seized
POOR ENGINE COMPRESSION
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POOR PERFORMANCE AT IDLE SPEED/
UNSATISFACTORY PERFORMANCE AT MEDIUM-HIGH SPEED
8-3
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Carburetor
Electrical system
Valves PROBABLE CAUSES•The starter piston fails to return freely
•Pilot jet obstructed or loose
•Pilot jet obstructed
•Pilot air screw wrongly set
•Idle speed wrongly set
(throttle valve stop screw)
•Throttle cable free play wrongly set
•Carburetor flooded
•Valve clearance wrongly set
Air filter
•Air filter element obstructed
POOR PERFORMANCE AT IDLE SPEED
See “FAILURE TO START/DIFFICULTIES IN STARTING”.
(FUEL SYSTEM, ELECTRICAL SYSTEM, COMPRESSION SYSTEM and Valve clearance)
Carburetor
PROBABLE CAUSES
•Petrol contains water or impurities or is adulterated
•Infiltrations of air
•Deformation of float
•Defective diaphragm
• Needle valve worn or scratched
•Needle valve seat insufficiently sealed
•Needle stop position incorrect
•Fuel level set wrongly
•Main jet obstructed or loose
•Main nozzle obstructed or loose
UNSATISFACTORY PERFORMANCE AT MEDIUM-HIGH SPEED
•Defective battery
•Defective spark plug
•Defective ignition unit
•Defective AC magneto
•Defective ignition coil
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DIFFICULTIES IN SHIFTING
8-4
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Clutch
Engine oil PROBABLE CAUSES•Clutch cable wrongly set
•Wrong position of push lever
•Irregular engagement of push lever and push
rod
•Pressure plate deformed
•Clutch springs not preloaded uniformly
•Reference marks not aligned
•Push rod broken
•Clutch gear assy nut loose or push rod deformed
•Primary driven gear bearing defective
•Driven plates deformed
•Driving plates deformed
•Clutch cable damaged
•Oil level over maximum
•Incorrect gradation (high viscosity)
•Degradation
SHIFTING IMPOSSIBLE
DIFFICULTIES IN SHIFTING
Shift shaft
Shift cam, shift fork PROBABLE CAUSES•Shift shaft deformed
•Groove with impurities or foreign bodies
•Shift fork stuck
•Shift fork guide bar deformed
THE SHIFT PEDAL FAILS TO MOVE
Transmission•Transmission gears struck
•Gears stuck by impurities or foreign bodies
•Wrong transmission assembly
Shift shaft
Shift fork PROBABLE CAUSES•Shift lever set wrongly
•Shift cam
stop lever fails to return freely
•Shift forks worn
Transmission
•Gear clutches worn
DISENGAGING GEARS
Shift cam
•Shaft cam with thrust free play
•Shift cam groove worn
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CLUTCH SLIDES OR FAILS TO RELEASE
8-5
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Clutch
Engine oil PROBABLE CAUSES•Clutch cable wrongly set
•Clutch springs loose
•Clutch spring yielded
•Friction plates worn
•Clutch plates worn
•Clutch improperly assembled
•Oil level below minimum
•Incorrect gradation (low viscosity)
•Degradation
CLUTCH SLIDES
CLUTCH SLIDES OR FAILS TO RELEASE
Refer to “SHIFTING IMPOSSIBLE” section.
CLUTCH FAILS TO RELEASE
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DEFECTIVE BRAKES/
OIL LEAKS OR MALFUNCTIONING OF FRONT FORK
8-6
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PROBABLE CAUSES
•Brake pads worn
•Brake disc worn
•Water in the brake fluid
•Brake fluid leak
•Brake fluid tank defective
•Bleed cap not sealed to calipers
•Union bolt loose
•Brake hose cracked
•Brake disc dirty or greasy
•Brake pads dirty or greasy
•Incorrect brake fluid level
POOR BRAKING
DEFECTIVE BRAKES
PROBABLE CAUSES
•Inner tube deformed, damaged or rusty
•Outer tube damaged or cracked
•Oil seal lip damaged
•Oil seal assembled incorrectly
•Oil level incorrect (excessive)
•Shock-absorber rod stop bolt loose
•O-ring on cap bolt broken
OIL LEAKS
PROBABLE CAUSES
•Inner tube deformed, damaged or rusty
•Outer tube deformed or damaged
•Fork spring damaged
•Piston worn or damaged
•Shock-absorber rod deformed or damaged
•Incorrect oil viscosity
•Incorrect oil level
MALFUNCTIONING
OIL LEAKS OR MALFUNCTIONING OF FRONT FORK
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UNSTABLE STEERING
8-7
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Handlebar
Steering PROBABLE CAUSES•Assembled crooked or incorrectly
•Handlebar crown assembled incorrectly
•Lower bracket crooked
•Lower steering column installed incorrectly
(threaded ring nuts not tightened correctly)
•Bearing or bearing tracks damaged
Front fork
•Oil level not the same in both tubes
•Spring broken
•Front fork crooked
Tyres
•Tyre pressure incorrect for type of road
•Tyre pressure incorrect
•Tyres worn non-uniformly
Wheels
•Wheels balanced incorrectly
•Wheel deformed
•Bearing loose
•Wheel axle deformed or loose
•Wheels excessively off-centre
Frame
•Deformed
•Head tube damaged
•Ball track installed incorrectly
Rear shock absorber
•Spring yielded
•Spring preloaded
•Oil leak
Rear arm
•Bushes or bearings consumed
•Deformed or damaged
Drive chain
•Chain set incorrectly
UNSTABLE STEERING
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DEFECTIVE FUNCTIONING OF LIGHTS AND INDICATORS
8-8
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PROBABLE CAUSES
•Incorrect bulb
•Excessive absorption of electrical accessories
•Difficulties in charging (charging coil broken
and/or rectifier/regulator defective)
•Uncertain connections
•Wrong negative earthing
•Insufficient contacts (main switch)
•Bulb gone
HEADLIGHT DOES NOT LIGHT
PROBABLE CAUSES
•Light relay/diode defective
•Incorrect bulb
•Rectifier/regulator defective
•Wrong negative earthing
•Main switch defective
•Bulbs gone
FREQUENT BURNING OF BULB PROBABLE CAUSES
•Wrong negative earthing
•Battery flat
•Defective direction indicator switch
•Indicator lamp relay defective
•Harness cut off
•Connector loose
•Bulb gone
DIRECTION INDICATORS FAIL TO TURN ON
PROBABLE CAUSES
•Indicator lamp relay defective
•Insufficient battery capacity
(battery almost flat)
•Bulb (front or rear) burnt out
•Direction indicator switch defective
DIRECTION INDICATORS FAIL TO TURN OFF
DEFECTIVE FUNCTIONING OF LIGHTS AND INDICATORS
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DEFECTIVE FUNCTIONING OF LIGHTS AND INDICATORS/ OVERHEATING OF ENGINE
8-9
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PROBABLE CAUSES
•Indicator lamp relay defective
•Insufficient battery capacity
(battery almost flat)
•Incorrect bulb
•Main switch or direction indicator switch defec-
tive
DELAYED TURNING ON OF INDICATORS
PROBABLE CAUSES
•Battery flat
•Main switch or horn switch defective
•Horn wrongly set
•Defective horn
•Harness cut off
THE HORN FAILS TO WORK
OVERHEATING OF ENGINE
PROBABLE CAUSES
•Incorrect bulb
•Indicator lamp relay defective
EXCESSIVE INDICATOR
INTERMITTENCE FREQUENCY
Ignition system
Fuel feed system PROBABLE CAUSES
•Incorrect electrode gap of spark plug
•Spark plug thermal gradation wrong
•Ignition unit defective
•Incorrect carburetor main jet (incorrect setting)
•Incorrect fuel level
•Air filter element obstructed
Engine compression
•Excess of carbon deposits
Engine oil
•Incorrect oil level
•Incorrect oil viscosity
•Incorrect oil gradation
Brake
•Pads fail to return freely (remains blocked)
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