CONTENTS
CHAPTER 1GENERAL
INFORMATION
DESCRIPTION ................. 1-1
MACHINE
IDENTIFICATION ............. 1-2
INCLUDED PARTS .......... 1-2
IMPORTANT
INFORMATION................. 1-2
CHECKING OF
CONNECTION .................. 1-3
SPECIAL TOOLS ............. 1-4
CONTROL FUNCTIONS .. 1-8
MULTI-FUNCTION
DISPLAY .......................... 1-9
STARTING AND
BREAK-IN ...................... 1-14
TORQUE-CHECK
POINTS........................... 1-16
CLEANING AND
STORAGE ...................... 1-17
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-12
LUBRICATION
DIAGRAMS .................... 2-18
CABLE ROUTING
DIAGRAM ....................... 2-20
CHAPTER 3 REGULAR
INSPECTION AND ADJUSTMENTS
PERIODIC MAINTENANCE
CHART FOR THE EMISSION
CONTROL SYSTEM
(For Canada) .................... 3-1
GENERAL MAINTENANCE
AND LUBRICATION CHART
(For Canada) .................... 3-2
MAINTENANCE
INTERVALS FOR
COMPETITION USE ......... 3-3
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-7
ENGINE ............................ 3-8
CHASSIS ........................ 3-19
ELECTRICAL ................. 3-29
CHAPTER 4 TUNING
ENGINE
(Except for Canada) ........ 4-1
CHASSIS .......................... 4-5
CHAPTER 5ENGINE
RADIATOR ....................... 5-1
CARBURETOR................. 5-4
AIR INDICTOIN
SYSTEM ......................... 5-12
CAMSHAFTS.................. 5-14
CYLINDER HEAD........... 5-19
VALVES AND VALVE
SPRINGS ........................ 5-21
CYLINDER AND
PISTON ........................... 5-25
CLUTCH ......................... 5-29 OIL FILTER ELEMENT
AND WATER PUMP .......5-34
BALANCER ....................5-38
OIL PUMP .......................5-40
KICK SHAFT AND
SHIFT SHAFT ................. 5-43
AC MAGNETO AND
STARTER CLUTCH........5-48
ENGINE REMOVAL........ 5-53
CRANKCASE AND
CRANKSHAFT ...............5-57
TRANSMISSION,
SHIFT CAM AND
SHIFT FORK ................... 5-63
CHAPTER 6
CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................6-1
FRONT BRAKE AND
REAR BRAKE ..................6-6
FRONT FORK ................. 6-16
HANDLEBAR..................6-23
STEERING ......................6-27
SWINGARM ....................6-31
REAR SHOCK
ABSORBER ....................6-36
CHAPTER 7
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........7-1
IGNITION SYSTEM...........7-3
ELECTRIC STARTING
SYSTEM............................7-5
CHARGING SYSTEM .....7-13
THROTTLE POSITION
SENSOR SYSTEM .........7-15
LIGHTING SYSTEM .......7-18
SIGNALING SYSTEM.....7-20
2-11
MAINTENANCE SPECIFICATIONS
Charging system:System type AC magneto----
Model (stator)/manufacturer 5UM 30/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 SH770AA/SHINDENGEN ----
Regulated voltage (AC) 12.5–13.5 V----
Regulated voltage (DC) 14.0–15.0 V----
Rectifier capacity (AC) 12 A----
Rectifier capacity (DC) 8 A----
Electric starting system: Type Constant mesh ----
Starter motor: Model/manufacturer 5UM01/YAMAHA ----
Operation voltage 12 V ----
Output 0.35 kW ----
Armature coil resistance 0.0189–0.0231 Ω at 20 °C (68 °F) ----
Brush overall length 7 mm (0.28 in) 3.5 mm (0.14
in)
Brush 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) ----
Starter relay: Model/manufacturer 2768090-A/JIDECO ----
Amperage rating 180 A ----
Coil winding resistance 4.2–4.6 Ω at 20 °C (68 °F) ----
Starting circuit cut-off relay: Model/manufacturer ACM33221 M38/MATSUSHITA ----
Coil winding resistance 75.69–92.51 Ω at 20 °C (68 °F) ----
Fuse (amperage×quantity): Main fuse 10 A × 1 ----
Reserve fuse 10 A × 1----
Item
StandardLimit
3-29
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:• Spark plug
2. Inspect:
• Electrode "1"Wear/damage →Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color →Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure: • Plug gap "a"Use a wire gauge or thickness
gauge.
Out of specification →Regap.
4. Clean the plug with a spark plug cleaner if necessary.
5. Tighten: • Spark plug
• Before installing a spark plug, clean the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw "1"
2. Attach: • Timing light
• Digital tachometerTo the ignition coil lead (orange
lead"1").
3. Adjust: • Engine idling speedRefer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check: • Ignition timing
Visually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range →Check ro-
tor and pickup assembly.
5. Install: • Timing mark accessing screw CHECKING AND CHARGING THE
BATTERY
Batteries generate explosive hy-
drogen gas and contain electrolyte
which is made of poisonous and
highly caustic sulfuric acid. There-
fore, always follow these preven-
tive measures:
• Wear protective eye gear when
handling or working near batter-
ies.
• Charge batteries in a well-venti- lated area.
• Keep batteries away from fire,
sparks or open flames (e.g.,
welding equipment, lighted ciga-
rettes).
• DO NOT SMOKE when charging or handling batteries.
• KEEP BATTERIES AND ELEC-
TROLYTE OUT OF REACH OF
CHILDREN.
• Avoid bodily contact with elec-
trolyte as it can cause severe
burns or permanent eye injury.
FIRST AID IN CASE OF BODILY
CONTACT:
EXTERNAL
• Skin — Wash with water.
• Eyes — Flush with water for 15
minutes and get immediate med-
ical attention.
INTERNAL
• Drink large quantities of water or
milk followed with milk of magne-
sia, beaten egg or vegetable oil.
Get immediate medical attention.
Charging time, charging amperage
and charging voltage for an MF
battery are different from those of
conventional batteries. The MF
battery should be charged as ex-
plained in the charging method il-
lustrations. If the battery is
overcharged, the electrolyte level
will drop considerably. Therefore,
take special care when charging
the battery.
Since MF batteries are sealed, it is
not possible to check the charge state
of the battery by measuring the spe-
cific gravity of the electrolyte. There-
fore, the charge of the battery has to
be checked by measuring the voltage
at the battery terminals.
Spark plug gap: 0.7–0.8 mm (0.028–
0.031 in)
Spark plug: 13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:YM-33277-A/90890-
03141
3-30
ELECTRICAL
1. Remove:• Seat
2. Disconnect: • Battery leads
(from the battery terminals)
First, disconnect the negative bat-
tery lead "1", and then the positive
battery lead "2".
3. Remove:• Battery band
• Battery
4. Measure:
• Battery charge
Measurement steps:
a. Connect a pocket tester "1" to the battery terminals.
• The charge state of an MF battery can be checked by measuring its
open-circuit voltage (i.e., the volt-
age when the positive terminal is
disconnected).
• No charging is necessary when the
opencircuit voltage equals or ex-
ceeds 12.8 V.
b. Check the charge of the battery, as shown in the charts and the fol-
lowing example.
Example
Open-circuit voltage = 12.0 V
Charging time = 6.5 hours
Charge of the battery = 20–30%
A. Relationship between the open-circuit voltage and the
charging time at 20 °C (68 °F)
(These values vary with the
temperature, the condition of
the battery plates, and the
electrolyte level.)
B. Open-circuit voltage
C. Charging time (hours)
D. Time (minutes)
E. Charging condition of the bat- tery
F. Ambient temperature 20 °C (68 °F)
a. Charging
b. Check the open-circuit volt-
age
5. Charge:
•Battery(refer to the appropriate charging
method illustration)
Do not quick charge a battery.
• Never remove the MF battery sealing caps.
• Do not use a high-rate battery charger since it forces a high-
amperage current into the bat-
tery quickly and can cause bat-
tery overheating and battery
plate damage.
• If it is impossible to regulate the charging current on the battery
charger, be careful not to over-
charge the battery.
• When charging a battery, be sure to remove it from the machine. (If
charging has to be done with the
battery mounted on the machine,
disconnect the negative battery
lead from the battery terminal.)
• To reduce the chance of sparks, do not plug in the battery charger
until the battery charger leads
are connected to the battery.
• Before removing the battery
charger lead clips from the bat-
tery terminals, be sure to turn off
the battery charger.
• Make sure the battery charger lead clips are in full contact with
the battery terminal and that they
are not shorted. A corroded bat-
tery charger lead clip may gener-
ate heat in the contact area and a
weak clip spring may cause
sparks.
• If the battery becomes hot to the touch at any time during the
charging process, disconnect
the battery charger and let the
battery cool before reconnecting
it. Hot batteries can explode!
• As shown in the following illus- tration, the open-circuit voltage
of an MF battery stabilizes about
30 minutes after charging has
been completed. Therefore, wait
30 minutes after charging is com-
pleted before measuring the
open-circuit voltage.
Tester positive probe →battery
positive terminal
Tester negative probe →battery
negative terminal
3-31
ELECTRICAL
Charging method using a variable voltage charger
3-32
ELECTRICAL
Charging method using a constant voltage charger
5-51
AC MAGNETO AND STARTER CLUTCH
• Pickup coil "3"
• Bolt (pickup coil) "4"
2. Install: •Holder "1"
•Bolt "2"
Pass the pickup coil lead and
charging coil lead under the holder
while taking care not to allow these
leads to get caught with each oth-
er. Also take care to pass the leads
so that they do not become loose
at the bend of the holder "a" in or-
der to avoid their contacting the
starter clutch drive gear.
Apply the sealant to the grommet of
the AC magneto lead.
3. Install:• Idle gear 2 "1"
• Dowel pin "2"
Apply the engine oil on the idle gear
2.
4. Install:• Idle gear plate "1"
• Bolt (idle gear plate) "2"
5. Install: •Washer "1"
• Bearing "2"
• Starter clutch drive gear "3"
•Washer "4"
Apply the engine oil on the washer,
bearing and starter clutch drive gear
inner circumference.
6. Install:
• Starter clutch "1"To rotor "2".
• Install the starter clutch with its plate side upward.
• While installing the starter clutch, push in the projections "a" one by
one on the clutch circumference.
• Push in the starter clutch until it hits the rotor.
7. Install:• Starter clutch assembly cover "1"To rotor "2".
Install the starter clutch assembly
cover by fitting its pawls "a" into the
groove "b" in the rotor.
8. Install:• Woodruff key "1"
• Rotor "2"
• Degrease the contact surfaces of the tapered portions of the crank-
shaft and rotor.
• When installing the woodruff key, make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
• When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
9. Install:• Washer (rotor)
• Nut (rotor) "1"
Use the sheave holder "2"
Tighten the rotor nut to 65 Nm (6.5
m•kg, 47 ft•lb), loosen and retighten
the rotor nut to 65 Nm (6.5 m•kg, 47
ft•lb).
Bolt (pickup coil): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt: 7 Nm (0.7 m•kg, 5.1
ft•lb)
YAMAHA Bond No. 1215
(ThreeBond
® No. 1215):
90890-85505
E
Bolt (idle gear plate): 10 Nm (1.0 m•kg, 7.2
ft•lb)
E
Nut (rotor):65 Nm (6.5 m•kg, 47
ft•lb)
Sheave holder: YS-1880-A/90890-
01701
6-36
REAR SHOCK ABSORBER
REAR SHOCK ABSORBER
REMOVING THE REAR SHOCK ABSORBEROrder Part name Q'ty Remarks Hold the machine by placing the suitable stand
under the engine. Refer to "HANDLING NOTE".
Seat and side cover Refer to "REMOVING THE SEAT, FUEL
TANK AND SIDE COVERS" section in the
CHAPTER 3.
Silencer Refer to "REMOVING THE EXHAUST PIPE
AND SILENCER" section in the CHAPTER 3.
Drain the coolant. Refer to "CHANGING THE COOLANT" sec-
tion in the CHAPTER 3.
Catch tank breather hose Disconnect at the catch tank side.
Catch tank hose Disconnect at the catch tank side.
Air induction hose (air cut-off valve-air filter case) Disconnect at the air filter case side.
Cylinder head breather hose Disconnect at the air filter case side.
Battery Refer to "CHECKING AND CHARGING THE
BATTERY" section in the CHAPTER 3.
Disconnect the starter relay coupler.
Starter motor lead Disconnect at the starter relay side.
1 Locking tie 4