CONTENTS
CHAPTER 1
GENERAL INFOR-
MATION
LOCATION OF
IMPORTANT LABELS ..... 1-1
DESCRIPTION ................. 1-4
CONSUMER
INFORMATION................. 1-5
INCLUDED PARTS .......... 1-5
IMPORTANT
INFORMATION................. 1-5
CHECKING OF
CONNECTION .................. 1-6
SPECIAL TOOLS ............. 1-7
CONTROL
FUNCTIONS ................... 1-12
MULTI-FUNCTION
DISPLAY ........................ 1-13
STARTING AND
BREAK-IN ...................... 1-18
TORQUE-CHECK
POINTS........................... 1-20
CLEANING AND
STORAGE ...................... 1-21
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-12
LUBRICATION
DIAGRAMS .................... 2-19
CABLE ROUTING
DIAGRAM ....................... 2-21
CHAPTER 3
REGULAR INSPEC-
TION AND AD-
JUSTMENTS
MAINTENANCE INTER-
VALS FOR COMPETITION
USE ................................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-17
ELECTRICAL ................. 3-27
CHAPTER 4
TUNING
ENGINE ............................ 4-1
CHASSIS .......................... 4-5
CHAPTER 5
ENGINE
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 .................... 5-39
OIL PUMP ....................... 5-41
KICK SHAFT AND
SHIFT SHAFT ................. 5-44
AC MAGNETO AND
STARTER CLUTCH ....... 5-49ENGINE REMOVAL........5-54
CRANKCASE AND
CRANKSHAFT ...............5-58
TRANSMISSION,
SHIFT CAM AND
SHIFT FORK ...................5-64
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 COMPO-
NENTS 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
1-18
STARTING AND BREAK-IN
STARTING AND BREAK-IN
FUEL
Always use the recommended fuel as
stated below. Also, be sure to use
new gasoline.
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to the engine inter-
nal parts such as valves, piston
rings, and exhaust system, etc.
If knocking or pinging occurs, use a
different brand of gasoline or higher
octane grade.
• For refueling, be sure to stop the
engine and use enough care not
to spill any fuel. Also be sure to
avoid refueling close to a fire.
• Refuel after the engine, exhaust
pipe, etc. have cooled off.
HANDLING NOTE
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 oper-
ate the machine in a well-ventilated
area.
• The carburetor on this machine
has a built-in accelerator pump.
Therefore, when starting the en-
gine, 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 be-
cause 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, per-
form the checks in the pre-opera-
tion check list.
AIR FILTER MAINTENANCE
According to "CLEANING THE AIR
FILTER ELEMENT" section in the
CHAPTER 3, apply the foam-air-filter
oil or its equivalent to the element.
(Excess oil in the element may ad-
versely affect engine starting.)
STARTING A COLD ENGINE
This model is equipped with an igni-
tion 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 en-
gine.
1. Inspect the coolant level.
2. Turn the fuel cock to "ON".
3. Push on 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 kick-
starter lever.
If the engine fails to start by pushing
the start switch, release the switch,
wait a few seconds, and then try
again. Each starting attempt should
be as short as possible to preserve
the battery. Do not crank the engine
more than 10 seconds on any one at-
tempt. If the engine does not start
with the starter motor, try using the
kickstarter lever.
• If the starter motor will not turn
when pushing the start switch,
stop pushing it immediately and
kick start the engine in order to
avoid the load on the motor.
• Do not open the throttle while
kicking the kickstarter lever. Oth-
erwise, the kickstarter lever may
kick back.
7. Return the cold starter knob to its
original position and run the en-
gine at 3,000–5,000 r/min for 1 or
2 minutes.
Since this model is equipped with an
accelerator pump, if the engine is
raced (the throttle opened and
closed), the air/fuel mixture will be too
rich and the engine may stall. Also
unlike a two-stroke engine, this model
can idle.
Do not warm up the engine for ex-
tended periods of time.
STARTING A WARM ENGINE
Do not operate the cold starter knob
and throttle. Pull the hot starter lever
"1" and start the engine by pushing
the start switch or by kicking the kick-
starter lever forcefully with a firm
stroke. As soon as the engine starts,
Release the hot starter lever to close
the air passage.
Restarting an engine after a fall
Pull the hot starter lever and start the
engine. As soon as the engine starts,
Release the hot starter lever to close
the air passage.
The engine fails to start
Pull the hot starter lever all the way
out and while holding the lever, kick
the kickstarter lever 10 to 20 times to
clear the engine. Then, restart the en-
gine. Refer to "Restarting an engine
after a fall". Recommended fuel:
Premium unleaded
gasoline only with a re-
search octane number
of 95 or higher.
3-2
MAINTENANCE INTERVALS FOR COMPETITION USE
CYLINDER
Inspect and clean●Inspect score marks.
Replace●Inspect wear.
CLUTCH
Inspect and adjust●●Inspect housing, friction plate, clutch
plate and spring.
Replace●
TRANSMISSION
Inspect●
Replace bearing●
SHIFT FORK, SHIFT CAM,
GUIDE BAR
Inspect●Inspect wear.
ROTOR NUT
Retighten●●
MUFFLER
Inspect and retighten●●
Clean●
Replace●
CRANK
Inspect and clean●●
CARBURETOR
Inspect, adjust and clean●●
AIR INDUCTION SYSTEM
Inspect and clean●● ●●
SPARK PLUG
Inspect and clean●●
Replace●
DRIVE CHAIN Use chain lube.
Lubricate, slack, alignment●●Chain slack: 48.0–58.0 mm (1.89–
2.28 in)
Replace●
COOLING SYSTEM
Check coolant level and leakage●●
Check radiator cap operation●
Replace coolant●Every two years
Inspect hoses●
OUTSIDE NUTS AND BOLTS
Retighten●●Refer to "STARTING AND BREAK-
IN" section in the CHAPTER 1.
AIR FILTER
Clean and lubricate●●Use foam air-filter oil or equivalent oil.
Replace● ItemAfter
break-
inEvery
race
Every
third
(or 500
km)Every
fifth (or
1,000
km)
As re-
quiredRemarks
3
5-36
OIL FILTER ELEMENT AND WATER PUMP
REMOVING THE IMPELLER
SHAFT
1. Remove:
• Impeller "1"
• Washer "2"
• Impeller shaft "3"
Hold the impeller shaft on its width
across the flats "a" with spanners,
etc. and remove the impeller.
REMOVING THE OIL SEAL
It is not necessary to disassemble the
water pump, unless there is an abnor-
mality such as excessive change in
coolant level, discoloration of coolant,
or milky transmission oil.
1. Remove:
• Bearing "1"
2. Remove:
• Oil seal "1"
CHECKING THE OIL DELIVERY
PIPE
1. Inspect:
• Oil delivery pipe "1"
Bend/damage→Replace.
Clogged→Blow.CHECKING THE IMPELLER SHAFT
1. Inspect:
• Impeller shaft "1"
Bend/wear/damage→Replace.
Fur deposits→Clean.
CHECKING THE IMPELLER SHAFT
GEAR
1. Inspect:
• Gear teeth "a"
Wear/damage→Replace.
CHECKING THE BEARING
1. Inspect:
•Bearing
Rotate inner race with a finger.
Rough spot/seizure→Replace.
CHECKING THE OIL SEAL
1. Inspect:
• Oil seal "1"
Wear/damage→Replace.INSTALLING THE OIL SEAL
1. Install:
• Oil seal "1"
• Apply the lithium soap base grease
on the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or numbers facing the
right crankcase cover "2".
2. Install:
• Bearing "1"
Install the bearing by pressing its out-
er race parallel.
INSTALLING THE IMPELLER
SHAFT
1. Install:
• Impeller shaft "1"
• Washer "2"
• Impeller "3"
• Take care so that the oil seal lip is
not damaged or the spring does not
slip off its position.
• When installing the impeller shaft,
apply the lithium soap base grease
on the oil seal lip and impeller shaft.
And install the shaft while turning it.
• Hold the impeller shaft on its width
across the flats "a" with spanners,
etc. and install the impeller.
Impeller:
14 Nm (1.4 m•kg, 10
ft•lb)
5-60
CRANKCASE AND CRANKSHAFT
REMOVING THE CRANKCASE BEARING
Order Part name Q'ty Remarks
TransmissionRefer to "TRANSMISSION, SHIFT CAM AND
SHIFT FORK" section.
Shift cam and shift fork Refer to "TRANSMISSION, SHIFT CAM AND
SHIFT FORK" section.
1 Oil seal 2
2 Bearing 10 Refer to removal section.
5-61
CRANKCASE AND CRANKSHAFT
DISASSEMBLING THE
CRANKCASE
1. Separate:
• Right crankcase
• Left crankcase
Separation steps:
a. Remove the crankcase bolts "1",
hose guide "2" and clutch cable
holder "3".
Loosen each bolt 1/4 of a turn at a
time and after all the bolts are loos-
ened, remove them.
b. Remove the right crankcase "4".
• Place the crankcase with its left
side downward and split it by insert-
ing a screwdriver tip into the split-
ting slit "a" in the crankcase.
• Lift the right crankcase horizontally
while lightly patting the case split-
ting slit and engine mounting boss
using a soft hammer, and leave the
crankshaft and transmission with
the left crankcase.
Use soft hammer to tap on the
case half. Tap only on reinforced
portions of case. Do not tap on
gasket mating surface. Work slow-
ly and carefully. Make sure the
case halves separate evenly. If the
cases do not separate, check for a
remaining case bolt or fitting. Do
not force.
c. Remove the dowel pins and O-
ring.
REMOVING THE CRANKSHAFT
1. Remove:
• Crankshaft "1"
Use the crankcase separating
tool "2".
Do not use a hammer to drive out
the crankshaft.
REMOVING THE CRANKCASE
BEARING
1. Remove:
•Bearing "1"
• Remove the bearing from the
crankcase by pressing its inner
race.
• Do not use the removed bearing.
CHECKING THE TIMING CHAIN
AND TIMING CHAIN GUIDE
1. Inspect:
• Timing chain
Cracks/stiff→Replace the timing
chain and camshaft sprocket as a
set.
2. Inspect:
• Timing chain guide
Wear/damage→Replace.CHECKING THE CRANKCASE
1. Inspect:
• Contacting surface "a"
Scratches→Replace.
• Engine mounting boss "b", crank-
case
Cracks/damage→Replace.
2. Inspect:
• Bearing
Rotate inner race with a finger.
Rough spot/seizure→Replace.
3. Inspect:
• Oil seal
Damage→Replace.
CHECKING THE CRANKSHAFT
1. Measure:
• Runout limit "a"
• Small end free play limit "b"
• Connecting rod big end side
clearance "c"
• Crank width "d"
Out of specification→Replace.
Use the dial gauge and a thick-
ness gauge.
Crankcase separating
tool:
YU-01135-B/90890-
01135
Dial gauge and stand:
YU-03097-B/90890-
01252
Standard
Run-
out
limit:0.030 mm
(0.0012 in)0.050
mm
(0.002
in)
Small
end
free
play:0.4–1.0 mm
(0.016–0.039 in)2.0 mm
(0.08 in)
Side
clear-
ance:0.150–0.450
mm (0.0059–
0.0177 in)0.500
mm
(0.02 in)
Crack
width:55.95–56.00
mm (2.203–
2.205 in)—
5-62
CRANKCASE AND CRANKSHAFT
CHECKING THE OIL STRAINER
1. Inspect:
• Oil strainer
Damage→Replace.
CHECKING THE OIL DELIVERY
PIPE 2
1. Inspect:
• Oil delivery pipe 2 "1"
• O-ring "2"
Damage→Replace.
• Oil orifice "a"
Clogged→Blow.
INSTALLING THE CRANKCASE
BEARING
1. Install:
• Bearing
• Bearing stopper
• Bolt (bearing stopper)
• Screw (bearing stopper) • Screw [bearing stopper (crank-
shaft)] "1"
To left and right crankcase.
• Install the bearing by pressing its
outer race parallel.
• To prevent the screw [bearing stop-
per (crankshaft)] from becoming
loose, crush the screw head periph-
ery "a" into the concave "b" using a
punch etc. In so doing, take care
not to damage the screwdriver re-
ceiving hole in the screw head.
INSTALLING THE CRANKSHAFT
1. Install:
• Crankshaft "1"
Use the crankshaft installing tool
"2", "3", "4" and "5".
• Hold the connecting rod at top dead
center with one hand while turning
the nut of the installing tool with the
other. Operate the installing tool un-
til the crankshaft bottoms against
the bearing.
• Before installing the crankshaft,
clean the contacting surface of
crankcase.
Do not use a hammer to drive in
the crankshaft.
A. For USA and CDN
B. Except for USA and CDN
2. Check:
• Shifter operation
• Transmission operation
Unsmooth operation→Repair.
3. Install:
• Oil strainer "1"
• Bolt (oil strainer) "2"
4. Apply:
• Sealant
On the right crankcase "1".
Clean the contacting surface of left
and right crankcase before applying
the sealant.
Bolt (bearing stopper):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Screw (bearing stopper):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Screw [bearing stopper
(crankshaft)]:
14 Nm (1.4 m•kg, 10
ft•lb)
Crankshaft installing pot
"2":
YU-90058/90890-01274
Crankshaft installing bolt
"3":
YU-90060/90890-01275
Adapter (M12) "4":
YU-90063/90890-01278
Spacer (crankshaft in-
staller) "5":
YM-91044/90890-04081
Bolt (oil strainer):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Yamaha bond No. 1215:
90890-85505
(Three bond No.1215®)
5-63
CRANKCASE AND CRANKSHAFT
5. Install:
• Dowel pin "1"
• O-ring "2"
• Right crankcase
To left crankcase.
• Apply the lithium soap base grease
on the O-ring.
• Fit the right crankcase onto the left
crankcase. Tap lightly on the case
with soft hammer.
• When installing the crankcase, the
connecting rod should be posi-
tioned at TDC (top dead center).
6. Tighten:
• Hose guide "1"
• Clutch cable holder "2"
• Bolt (crankcase) "3"
Tighten the crankcase tightening
bolts in stage, using a crisscross pat-
tern.
7. Install:
• Oil delivery pipe 2 "1"
• O-ring "2"
• Bolt (oil delivery pipe 2) "3"
Apply the lithium soap base grease
on the Orings.
8. Install:
• Timing chain "1"
• Timing chain guide (intake side)
"2"
• Bolt (timing chain guide) "3"
9. Remove:
• Sealant
Forced out on the cylinder mating
surface.
10. Apply:
• Engine oil
To the crank pin, bearing and oil
delivery hole.
11. Check:
• Crankshaft and transmission op-
eration.
Unsmooth operation→Repair. Bolt (crankcase):
12 Nm (1.2 m•kg, 8.7
ft•lb)
Bolt (oil delivery pipe 2):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (timing chain guide):
10 Nm (1.0 m•kg, 7.2
ft•lb)