Page 24 of 754
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM
...........................6-1
MAP-CONTROLLED CDI UNIT
.................6-2
IGNITION SYSTEM
....................................6-3
ELECTRIC STARTING SYSTEM
..............6-7
CHARGING SYSTEM
..............................6-17
TPS (THROTTLE POSITION SENSOR)
SYSTEM
...................................................6-19
LIGHTING SYSTEM
................................6-24
CHAPTER 7
TUNING
ENGINE
......................................................7-1
CHASSIS
.................................................7-10
Page 39 of 754

GEN
INFO
1 - 8
SPECIAL TOOLS
YM-01442, 90890-01442 Fork seal driver
This tool is used when install the fork oil seal.YM-01442 90890-01442
YS-1880-A, 90890-01701 Sheave holder
This tool is used for when loosening or tightening the
flywheel magneto securing nut.YS-1880-A 90890-01701
YU-3112-C, 90890-03112 Yamaha pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-3112-C 90890-03112
YM-33277-A, 90890-03141 Timing light
This tool is necessary for checking ignition timing.YM-33277-A 90890-03141
YM-4019, 90890-04019 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.YM-4019 90890-04019
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
YM-4116, 90890-04116
YM-4097, 90890-04097Valve guide remover
Intake 4.5 mm (0.18 in)
Exhaust 5.0 mm (0.20 in)
This tool is needed to remove and install the valve
guide.YM-4116
YM-409790890-04116
90890-04097
YM-4117, 90890-04117
YM-4098, 90890-04098Valve guide installer
Intake
Exhaust
This tool is needed to install the valve guide.YM-4117
YM-409890890-04117
90890-04098
YM-4118, 90890-04118
YM-4099, 90890-04099Valve guide reamer
Intake 4.5 mm (0.18 in)
Exhaust 5.0 mm (0.20 in)
This tool is needed to rebore the new valve guide.YM-4118
YM-4099 90890-04118
90890-04099
Part number Tool name/How to use Illustration
Page 40 of 754
GEN
INFO
1 - 9
SPECIAL TOOLS
YM-04142, 90890-04142 Rotor puller
This tool is used to remove the flywheel magneto.YM-04142 90890-04142
YM-34487
90890-06754Dynamic spark tester
Ignition checker
This instrument is necessary for checking the ignition
system components.YM-34487 90890-06754
ACC-QUICK-GS-KT
90890-85505Quick gasket
YAMAHA Bond No. 1215
This sealant (Bond) is used for crankcase mating
surface, etc.ACC-QUICK-GS-KT 90890-85505
Part number Tool name/How to use Illustration
Page 60 of 754

1 - 15
GEN
INFO
STARTING AND BREAK-IN
STARTING AND BREAK-IN
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
CAUTION:
The carburetor on this machine has a
built-in accelerator pump. Therefore,
when starting the engine, do not operate
the throttle or the spark plug will foul.
Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the
engine to start.
Before starting the machine, perform the
checks in the pre-operation check list.
AIR FILTER MAINTENANCE
According to “AIR FILTER CLEANING” section
in the CHAPTER 3, apply the foam-air-filter oil
or its equivalent to the element. (Excess oil in
the element may adversely affect engine start-
ing.)
STARTING A COLD ENGINE
NOTE:
This model is equipped with an ignition circuit
cut-off system. The engine can be started
under the following conditions.
When the transmission is in neutral.
When the clutch is disengaged with the
transmission in any position. However, it is
recommended to shift into neutral before
starting the engine.
1. Inspect the coolant level.
2. Turn the fuel cock to “ON”.
3. Push the main switch to “ON”.
4. Shift the transmission into neutral.
5. Fully open the cold starter knob 1.
6. Start the engine by pushing the start
switch or by kicking the kickstarter.
Page 78 of 754
SPEC
2 - 3
GENERAL SPECIFICATIONS
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI
Generator system AC magneto
Battery type YTZ7S
Battery voltage/capacity 12 V/6 AH
Specific gravity 1.310
Headlight type: Quartz bulb (halogen)
Bulb wattage
×
quantity:
Headlight 12 V 60/55 W
×
1
Taillight 12 V 21/5 W
×
1
Page 93 of 754

SPEC
2 - 18
MAINTENANCE SPECIFICATIONS
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Advancer type Electrical ----
C.D.I.:
Pickup coil resistance (color) 248 ~ 372 Ω at 20 ˚C (68 ˚F)
(White – Red)----
CDI unit-model/manufacturer 5TJ50/YAMAHA (For USA)
5TJ60/YAMAHA
(Except for USA)----
----
Ignition coil:
Model/manufacturer 5TA-10/DENSO ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.08 ~ 0.10 Ω at 20 ˚C (68 ˚F) ----
Secondary winding resistance 4.6 ~ 6.8 kΩ at 20 ˚C (68 ˚F) ----
Charging system:
System type AC magneto ----
Model (stator)/manufacturer 5TJ-01/YAMAHA ----
Normal output 14 V/120 W at 5,000 r/min ----
Charging coil resistance (color) 0.288 ~ 0.432 Ω at 20 ˚C (68 ˚F)
(White – Ground)----
Lighting coil resistance (color) 0.224 ~ 0.336 Ω at 20 ˚C (68 ˚F)
(Yellow – Ground)----
Rectifier/regulator:
Regulator type Semiconductor short circuit ----
Model/manufacture SH712AA/SHINDENGEN ----
Regulated voltage (AC) 13.0 ~ 14.0 V ----
Regulated voltage (DC) 14.1 ~ 14.9 V ----
Rectifier capacity (AC) 12 A ----
Rectifier capacity (DC) 8 A ----
Electric starting system:
Type Constant mesh ----
Starter motor:
Model/manufacturer 5TJ01/YAMAHA ----
Operation voltage 12 V ----
Output 0.48 kW ----
Armature coil resistance 0.0117 ~ 0.0143 Ω at 20 ˚C
(68 ˚F)----
Brush overall length 7 mm (0.28 in) 3.5 mm
(0.14 in)
Brash quantity 2 pcs. ----
Spring force 3.92 ~ 5.88 N
(400 ~ 600 g, 14.1 ~ 21.2 oz)----
Commutator diameter 17.6 mm (0.69 in) 16.6 mm
(0.65 in)
Mica undercut (depth) 1.5 mm (0.06 in) ----
Page 164 of 754

2 - 25
SPECCABLE ROUTING DIAGRAM
1Hot starter cable
2Clutch cable
3Throttle cable (return)
4Throttle cable (pull)
5Ignition coil
6Negative battery lead
7Starter motor lead
8Coolant reservoir tank
breather hose
9Rectifier/regulator
0Cable holder
ACoolant reservoir hose
BRectifier/regulator lead
CClamp
DCDI unit lead
ECDI unit
FCDI unit band
GCDI unit stay (frame)
HCable bracketÅPass the throttle cables, clutch
cable and hot starter cable through
the cable guides.
ıPass the throttle cables, clutch
cable and hot starter cable between
the radiator and frame, then over
the middle radiator mounting boss.
ÇPass the throttle cables and clutch
cable on the outside of the ignition
coil.
ÎPass the carburetor breather hose
(throttle cable cover) through the
hose holder.
‰Fasten the coolant reservoir tank
breather hose and carburetor
breather hoses together with a
plastic locking tie.ÏFasten the grommet of the clutch
cable with the cable holder.
ÌFasten the rectifier/regulator lead to
the frame with a plastic locking tie
and cut off the tie end.
ÓFasten the CDI unit lead to the
frame with a plastic locking tie ends
at the lower of the frame and cut off
the tie end.
ÈInsert the CDI unit band over the
CDI unit stay (frame) as far as pos-
sible.
ÔFasten the starter motor lead and
negative battery lead to the cable
bracket in its slot with a plastic lock-
ing tie and cut off the tie end.
Do not allow the rectifier/regulator
lead to slacken.
Page 184 of 754

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-10
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-26 ~ 32
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-33 ~ 36
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-44 ~ 45
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-45 ~ 46
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-36 ~ 43
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks.—
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-47
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-19
Lead connectorsCheck that the AC magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 21