Page 104 of 140
8-29
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2. Push the throttle lever forward until it stops
and hold it in this position.
3. Check through each carburetor window to see
if the punch mark on the throttle valve is at the
specified position.
4. If not, loosen the locknut and turn the adjust-
ing nut until the specified position is obtained.5. Move the throttle lever a few times and re-
check the position.
6. Install the fuel tank, side cover, radiator cover
and air filter case cover.
7. Connect the fuel hoses.
8. Install the seat.
EBU24020
Adjusting the engine idling speed
The engine idling speed must be checked and, if
necessary, adjusted as follows at the intervals
specified in the periodic maintenance and lubrica-
1. Punch mark
2. Specified position: 0–1mm
1
2
1. Adjusting nut
2. Locknut
1
2
Page 105 of 140
8-30
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tion chart.
NOTE:
A diagnostic tachometer is needed to make this
adjustment.
The carburetor synchronization and the throttle
cable free play must be checked, and adjusted if
necessary, before adjusting the engine idling
speed.
1. Start the engine and warm it up.
NOTE:
The engine is warm when it quickly responds to the
throttle.
2. Attach the tachometer to the spark plug lead.
3. Turn in both pilot air screws until they lightly
seat.
4. Turn out both pilot air screws to specification.
(See the “Changing the carburetor settings”
section on the page 8-22.)5. Remove the seat. (See page 4-11.)
6. Check the engine idling speed and, if neces-
sary, adjust it to specification by turning the
throttle stop screws at the carburetors. To in-
crease the engine idling speed, turn the throt-
tle stop screws in direction (a), and to
decrease it, turn the screws in direction (b).
1. Pilot air screw
1
Page 106 of 140

8-31
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CAUTION:
ECB00510
The throttle stop screws were preset at the
factory. When adjusting the idling speed,
turn both throttle stop screws the same
amount, otherwise the carburetor synchroni-
zation will be incorrect.
Adjusting the pilot air screws and the idling
speed are separate procedures, but they
must be adjusted at the same time to achieve
optimum engine performance.
NOTE:
If the specified idling speed cannot be obtained as
described above, have a Yamaha dealer make the
adjustment.
7. Install the seat.
EBU24043
Adjusting the throttle cable free play
The throttle cable free play should be checked
and, if necessary, adjusted at the intervals speci-
fied in the periodic maintenance and lubrication
chart.
The throttle cable free play should measure 4.0–
6.0 mm (0.16–0.24 in) at the throttle lever. Period-
ically check the throttle cable free play and, if nec-
essary, adjust it as follows.
NOTE:
The engine idling speed must be checked, and ad-
justed if necessary, before adjusting the throttle ca-
ble free play.
1. Loosen the locknut.
2. To increase the throttle cable free play, turn
the adjusting bolt in direction (a). To decrease
1. Throttle stop screw
Engine idling speed:
1450–1550 r/min
1
(b)
(a)
(a)
(b)
Page 117 of 140

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CAUTION:
ECB00560
The drive chain must be lubricated after wash-
ing the ATV or riding in the rain.
1. Clean the drive chain with kerosene and a
small soft brush.
CAUTION:
ECB00570
To prevent damaging the O-rings, do not clean
the drive chain with steam cleaners, high-pres-
sure washers or inappropriate solvents.
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a
special O-ring chain lubricant.
CAUTION:
ECB00580
Do not use engine oil or any other lubricants
for the drive chain, as they may contain sub-
stances that could damage the O-rings.
EBU24900
Checking and lubricating the cables
The operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
WARNING
EWB02130
Inspect cables frequently and replace if dam-
aged. Corrosion can result when the cable
sheaths become damaged, and cables can
also become frayed or kinked, which could re-
strict the operation of controls and lead to an
accident or injury.
1. O-ring
Recommended lubricant:
Engine oil
Page 127 of 140
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EBU25841
Troubleshooting charts
Starting problems or poor engine perfor- mance
Check the fuel level in
the fuel tank.1. Fuel
There is
enough fuel.
There is
no fuel.
Supply fuel.
Operate the kickstarter.2. Compression
There is compression.
There is
no compression.Check the ignition.
Have a Yamaha dealer
check the ATV.
Remove the spark plugs
and check the electrodes.3. Ignition
Wet
DryWipe off with a dry cloth and correct the
spark plug gaps, or replace the spark plugs.
Have a Yamaha dealer check the ATV.The engine does not start.
Have a Yamaha dealer check the ATV.
Open the throttle halfway and operate
the kickstarter.
Check the compression.
The engine does not start.
Check the compression.
Page 128 of 140
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Engine overheating
WARNING
EWB02290
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.
NOTE:
If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the rec-
ommended coolant as soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer check
and repair the cooling system.Add coolant. (See NOTE.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
Page 138 of 140

INDEX
A
Accessories and loading ................................................ 6-6
Air filter element, cleaning ............................................ 8-17
B
Brake and clutch levers, checking and lubricating ....... 8-43
Brake and shift pedals, checking and lubricating ......... 8-43
Brake fluid, changing.................................................... 8-34
Brake fluid level, checking............................................ 8-33
Brake lever ..................................................................... 4-5
Brake lever free play, checking the front ...................... 8-34
Brake light switches ..................................................... 8-38
Brake pads, checking the front and rear ...................... 8-32
Brake pedal .................................................................... 4-5
Brake pedal position, checking .................................... 8-35
Brakes, front and rear .................................................... 5-3
C
Cables, checking and lubricating ................................. 8-42
Carburetor settings, changing ...................................... 8-22
Chassis fasteners........................................................... 5-7
Cleaning ......................................................................... 9-1
Clutch lever .................................................................... 4-4
Clutch lever free play, adjusting ................................... 8-38
Coolant ................................................................. 5-3
,
8-12
D
Drive chain ..................................................................... 5-4
Drive chain, lubricating ................................................. 8-41Drive chain slack .......................................................... 8-39
E
Engine break-in .............................................................. 6-4
Engine, cold start ........................................................... 6-1
Engine idling speed ...................................................... 8-29
Engine, starting a warm ................................................. 6-2
Engine stop switch ......................................................... 4-2
F
Fuel ................................................................................ 4-8
Fuel and 2-stroke engine oil mixing ratio ....................... 5-3
Fuel cock ........................................................................ 4-9
Fuel tank cap.................................................................. 4-7
H
Handlebar switches ........................................................ 4-2
Headlight beam, adjusting............................................ 8-48
Headlight bulb, replacing.............................................. 8-45
I
Identification numbers .................................................. 11-1
Instruments, lights and switches .................................... 5-7
K
Key identification number ............................................. 11-1
Kickstarter ...................................................................... 4-7
L
Label locations ............................................................... 2-1
Light switch .................................................................... 4-2
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