Page 282 of 382
ENGINE REASSEMBLY
5-78
ENG
9. Install:
•Carburetor Screw (clamp): 2 Nm (0.2 mkg)
Screw (seat): 10 Nm (1.0 mkg)
See section “CARBURETOR-INSTALLA-
TION” in CHAPTER 6.
10. Adjust:
•Throttle cable free play
Free play: 3 ~ 5 mm
Engine idle speed:1.150 ~ 1.450 rpm
See section “THROTTLE CABLE FREE
PLAY ADJUSTMENT” in CHAPTER 3.
11. Install:
•Fuel tank
Do not start the engine until it is filled with oil.
CAUTION:
12. Fill with:
•Engine oil Amount of oil (total): 3.0 litres
13. Check:
•Engine idle speed
See section “IDLE SPEED ADJUST-
MENT” in CHAPTER 3.
14. Install:
•Seat
See section “ENGINE OIL REPLACE-
MENT” in CHAPTER 3.
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Page 306 of 382

ELECTRICAL CIRCUIT DIAGRAM
7-2
ELEC
B Black B/Y Black/Yellow
Br Brown Br/B Brown/Black
Ch Chocolate Br/W Brown/White
Dg Deep green G/B Green/Black
G Green G/R Green/Red
Gy Grey G/W Green/White
L Blue G/Y Green/Yellow
Or Orange L/R Blue/Red
P Pink L/W Blue/White
R Red L/Y Blue/Yellow
Sb Sky-blue R/B Red/Black
W White R/W Red/White
Y Yellow R/Y Red/Yellow
B/R Black/Red W/L White/Blue
B/W Black/White Y/R Yellow/Red
(1) AC generator/Pickup coil
(2) Rectifier/Regulator
(3) Battery
(4) Starter relay
(5) Starting motor
(6) Fuse
(7) Main switch
(8) Right handlebar switch
(9) Engine stop switch
(10) Starter switch
(11) Diode
(12) Clutch switch
(13) Sidestand switch
(14) Neutral switch
(15) Diode
(16) Ignitor unit
COLOUR CODE (17) Ignition coil
(18) Left handlebar switch
(19) Horn switch
(20) Diode
(21) Pass switch
(22) Dimmer switch
(23) Flasher switch
(24) Horn
(25) Flasher relay
(26) Headlight
(27) Flasher light
(28) Relay assy
(29) Front brake switch
(30) Rear brake switch
(31) Tail/stop light
(32) Meter
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Page 316 of 382
IGNITION SYSTEM
7-12
ELEC
The diagram illustrates the ignition circuit inside the motorcycles electric system. NOTE:
For the colour code and legend, see page 7-2.
(1) AC generator/Pickup coil
(2) Rectifier/Regulator
(3) Battery
(6) Fuse
(7) Main switch
(9) Engine stop switch
(11) Diode (12) Clutch switch
(13) Sidestand switch
(14) Neutral switch
(15) Diode
(16) Ignitor unit
(17) Ignition coil
\f
\f\f
\f
\f
\f\f
\f\f
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Page 317 of 382

ELECIGNITION SYSTEM
7-13
DIAGNOSTICS IF THE IGNITION SYSTEM WERE TO STOP WORKING (NO OR INTERMITTENT SPARK)
Procedure
Check:
1. Fuse
2. Battery
3. Spark plug
4. Amplitude of ignition spark
5. Spark plug cap resistance
6. Ignition winding resistance 7. Main switch
8. Engine stop switch
9. Sidestand switch
10. Neutral switch
11. Clutch switch
12. Pick-up coil resistance
13. Wiring connections (whole connection sys- tem)
NOTE:
Before making the inspections mentioned, remove the following parts:
1. Seat
2. Rear cowling 3. Fuel tank
4. Cowling (headlight)
•To check functioning defects use the following special tools.
Dinamic spark tester: P/N. 90890-06754
Pocket tester:P/N. 90890-03112
1. Fuse
•Check the fuse for continuity.
Refer to “CHECKING THE FUSES” in
Chapter 3.
•Is the fuse OK?
YES
2. Battery
•Check the condition of the battery.
Refer to “CHECKING AND CHARGING
THE BATTERY” in Chapter 3.
Min. open-circuit voltage:
2.8 V or more at 20°C (68°F)
•Is the battery OK?
NO
Replace the fuse.
NO
•Clean the battery terminals.
•Recharge or replace the battery.
YES
*
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Page 342 of 382
CHARGING SYSTEM
7-38
ELEC
3. Charging voltage
•Connect the inductive rev counter to the
spark plug cable.
•Connect the pocket tester (DC 20V) to the
battery, as shown.
Tester terminal (+) ➔ Battery terminal (+)
Tester terminal (-) ➔Battery terminal (-)
•Start the engine and rev to about 5,000 rpm.
•Check the charging voltage.
Charging voltage:
14.0V at 5,000 rpm
4. Stator coil resistance.
•Disconnect the AC generator connector
from the harness.
•Connect the pocket tester ( Ωx 1) to the sta-
tor coils.
Stator coils (1)
Tester terminal (+) ➔White cable (1)
Tester terminal (-) ➔White cable (2))
*
NOTE:
Use a fully charged battery.
OUT OF SPECIFICATIONS
IN COMPLIANCE WITH
SPECIFICATIONS
Replace the battery.
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Page 370 of 382

TRBL
SHTG
?
CHAPTER 8°
TROUBLESHOOTING
FAILURE TO START/DIFFICULTIES IN STARTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
ELECTRICAL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
POOR ENGINE COMPRESSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
POOR PERFORMANCE AT IDLE SPEED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
UNSATISFACTORY PERFORMANCE AT MEDIUM-HIGH SPEED . . . . . . . . . . . . . . . . . 8-3
DIFFICULTIES IN SHIFTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
SHIFTING IMPOSSIBLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
THE SHIFT PEDAL FAILS TO MOVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
DISENGAGING GEARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
CLUTCH SLIDES OR FAILS TO RELEASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
CLUTCH SLIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
CLUTCH FAILS TO RELEASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
DEFECTIVE BRAKES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
POOR BRAKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
OIL LEAKS OR MALFUNCTIONING OF FRONT FORK . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
OIL LEAKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
MALFUNCTIONING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
UNSTABLE STEERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
DEFECTIVE FUNCTIONING OF LIGHTS AND INDICATORS . . . . . . . . . . . . . . . . . . . . . 8-8
POOR HEADLIGHT ILLUMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
FREQUENT BURNING OF BULB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
DIRECTION INDICATORS FAIL TO TURN ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
DIRECTION INDICATORS FAIL TO TURN OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
DELAYED TURNING ON OF INDICATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
EXCESSIVE INDICATOR INTERMITTENCE FREQUENCY . . . . . . . . . . . . . . . . . . . 8-9
THE HORN FAILS TO WORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
OVERHEATING OF ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
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Page 373 of 382

FAILURE TO START/
DIFFICULTIES IN STARTING
8-2
TRBL
SHTG
?
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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Page 375 of 382

DIFFICULTIES IN SHIFTING
8-4
TRBL
SHTG
?
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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