2002 YAMAHA YFM660R engine

5-19
WARNING
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.
EBU00498
Chain
Check the general condition of the chain and
check the chain slack before every ride. Lubricate
and adjust the chain as necessary. (See pages
8-79 ~ 8-85 for details.)
U5LP61.book Page 19 Monday, August 27, 2001 3:49 PM

5-21
EBU00151
Throttle lever
Check to see that the throttle lever operates cor-
rectly. It must open smoothly and spring back to
idle position when released. Repair as necessary
for proper operation.
EBU00152
Fittings and Fasteners
Always check the tightness of chassis fittings and
fasteners before a ride. Take the machine to a
Yamaha dealer or refer to the Service Manual for
correct tightening torque.
EBU00991
Lights
Check the headlights and tail/brake light to make
sure they are in working condition. Repair as nec-
essary for proper operation.
EBU00912
Switches
Check the operation of the light switch, engine
stop switch and any other switches. Repair as nec-
essary for proper operation.
U5LP61.book Page 21 Monday, August 27, 2001 3:49 PM

6-3
EBU00815
Starting a cold engine
WARNING
Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or do
not work smoothly, you could be unable to
control the ATV, which could lead to an acci-
dent or collision. 1. Set the parking brake.
2. Turn the fuel cock to “ON”.
3. Turn the main switch to “ON” and the engine
stop switch to “”.
4. Shift the transmission into neutral.
U5LP61.book Page 3 Monday, August 27, 2001 3:49 PM

6-5 1. Fully open 2. Half open
3. Closed
1. Complètement ouvert 2. Mi-ouvert
3. Fermé
1. Abre completamente 2. Semiabierto
3. Cerrado
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. The neu-
tral indicator light should come on. If the light
does not come on, ask a Yamaha dealer to
inspect it.


When the clutch is disengaged with the trans-
mission in any position. However, it is recom-
mended to shift into neutral before starting
the engine.
5. Use the starter (choke) in reference to the fig-
ure:
Position
1: Cold engine start-
ambient temperature below 5°
C.
Position
2: Cold engine start-
ambient temperature at 0°
C ~
30°
C and warming up position.
Position
3: Cold engine start-
ambient temperature above 25°
C
and warm engine start position.
U5LP61.book Page 5 Monday, August 27, 2001 3:49 PM

6-7
6. Completely close the throttle lever and start
the engine by pushing the start switch.NOTE:If the engine fails to start, release the start switch,
then push it again. Pause a few seconds before
the next attempt. Each cranking should be as short
as possible to preserve battery energy. Do not
crank the engine more than 10 seconds on each
attempt. 7. If the engine is started with the starter (choke)
in position
1, the starter (choke) should be
returned to position
2 to warm up the engine.
If the engine is started with the starter (choke)
in position
2, keep the starter (choke) in this
position to warm up the engine.
8. Continue warming up the engine until it idles
smoothly and return the starter (choke) to po-
sition
3 before riding.CAUTION:
See the “Engine break-in” section prior to op-
erating engine for the first time.
U5LP61.book Page 7 Monday, August 27, 2001 3:49 PM

6-9
EBU00180
Starting a warm engine
To start a warm engine, refer to the “Starting a cold
engine” section. The starter (choke) should not be
used. The throttle should be opened slightly.
EBU00538
Warming up
To get maximum engine life, always warm up the
engine before starting off. Never accelerate hard
with a cold engine! To see whether or not the en-
gine is warm, check if it responds to the throttle
normally with the starter (choke) turned off.NOTE:When the parking brake is used, engine speed is
limited to 2,300 r/min. Be sure the parking brake is
released before moving the throttle lever. Other-
wise, the engine will misfire, preventing normal op-
eration.
U5LP61.book Page 9 Monday, August 27, 2001 3:49 PM

6-15 1. Shift pedal N. Neutral position
R. Reverse
1. Pédale de sélection N. Point mort
R. Marche arrière
1. Pedal del cambio N. Posición de punto muerto
R. Marcha atrás
EBU00199
Shifting
This model has a 5-speed forward and 1-speed re-
verse transmission. The transmission allows you
to control the amount of power you have available
at a given speed or for starting, accelerating,
climbing hills, etc. To shift into neutral, return the
throttle lever to its original position, apply the
clutch and repeatedly depress the shift pedal until
it stops. When it stops, it will be in first gear. Raise
the pedal slightly to neutral.CAUTION:_

Do not coast for long periods with the en-
gine off, and do not tow the machine a long
distance. Even in neutral position, the
transmission is only properly lubricated
when the engine is running. Inadequate lu-
brication may cause damage.


Always use the clutch when changing
gears. The engine, transmission and drive
train are not designed to withstand the
shock of forced shifting and can be dam-
aged by shifting without the clutch.
_
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6-17
EBU00204
To start out and accelerate:
1. Release the throttle lever.CAUTION:
Always close the throttle while shifting gears.
Otherwise, damage to the engine and drive
train may result.2. Pull the clutch lever to disengage the clutch.
3. Shift into first gear.
4. Open the throttle gradually and at the same
time, release the clutch lever slowly.
5. Once the machine has attained adequate
speed, release the throttle, and at the same
time, quickly pull in the clutch lever.
U5LP61.book Page 17 Monday, August 27, 2001 3:49 PM