engine YAMAHA BRUIN 250 2005 Owner's Manual

6-3
EBU15560
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.
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6-5 a. Starter (choke) 1. Fully-open
2. Half open 3. Closed
a. Starter (enrichisseur) 1. Complètement ouvert
2. Mi-ouvert 3. Fermé
a. Starter (choke) 1. Abre completamente
2. Semiabierto 3. Cerrado
NOTE:_

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.


The engine can be started in any gear if the
rear brake lever is applied. However, it is rec-
ommended 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 tempera-
ture below 5°C.
Position
2: Cold engine start-ambient tempera-
ture at 0°C–30°C and warming up
position.
Position
3: Cold engine start-ambient tempera-
ture above 25°C and warm engine
start position.
6. Completely close the throttle lever and start
the engine by pushing the start switch.
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6-7
NOTE:_

If the engine fails to start, release the start
switch, then push the start switch again.
Pause a few seconds before the next at-
tempt. Each cranking should be as short as
possible to preserve battery energy. Do not
crank the engine more than 10 seconds on
each attempt.


If the battery is discharged, pull the recoil
starter to start the engine.
_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 en-
gine. If the engine is started with the starter
(choke) in position
2, keep the starter
(choke) in this position to warm up the en-
gine.
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 the engine for the first time. _
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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.
EBU00182
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.
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6-15 1. Shift pedal N. Neutral position
1. Pédale de sélection N. Point mort
1. Pedal del cambio N. Punto muerto
EBU02000
Shifting
This model has a 5-speed forward transmission
with centrifugal automatic clutch. The transmission
allows you to control the amount of power you
have available at a given speed or for starting ac-
celerating, climbing, etc. To shift into neutral, re-
turn the throttle lever to its original position and
repeatedly depress the shift pedal until it stops.CAUTION:_ Do not coast for long periods with the engine
off, and do not tow the machine a long dis-
tance. Even with gears in neutral, the transmis-
sion is only properly lubricated when the
engine is running. Inadequate lubrication may
damage the transmission. _
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6-17
EBU00650
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. Shift into first gear and release the shift ped-
al.
3. Open the throttle gradually.
4. Once the machine has attained adequate
speed, release the throttle lever.
5. Shift into second gear and release the shift
pedal.
6. Open the throttle gradually.
7. Follow the same procedure when shifting to
the next higher gear.
WARNING
Always open the throttle gradually. Opening
the throttle abruptly would increase the
chance of an accident. It could make the ma-
chine wheelie or overturn.
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6-19
EBU00208
To decelerate:
When slowing down or stopping, release the throt-
tle and apply the brakes smoothly and evenly. As
you slow down, shift to a lower gear. Be sure that
the engine has sufficiently slowed before engaging
a lower gear. Improper use of the brakes or shift-
ing can cause the tires to lose traction, reducing
control and increasing the possibility of an acci-
dent.
WARNING
Make sure the engine has sufficiently slowed
before shifting to a lower gear. Engaging a low-
er gear when the engine speed is too high
could make the wheels stop rotating. This
could cause loss of control, an accident and
injury. It could also cause engine or drive train
damage.
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6-21
EBU02092
Engine break-in
There is never a more important period in the life of
your machine than the period between zero and
20 hours.
For this reason, we ask that you carefully read the
following material. Because the engine is brand
new, you must not put an excessive load on it for
the first several hours of running. During the first
20 hours, the various parts in the engine wear and
polish themselves to the correct operating clear-
ances.
During this period, prolonged full throttle operation
or any condition which might result in excessive
engine heating must be avoided. However, mo-
mentary (2–3 seconds maximum) full throttle oper-
ation under load does not harm the engine. Each
full throttle acceleration sequence should be fol-
lowed with a substantial rest period for the engine
by cruising at lower r/min so the engine can rid it-
self of the temporary build up of heat.
If any abnormality is noticed during this period,
consult a Yamaha dealer.
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6-23 1. Locked position
1. Position verrou bloqué
1. Posición bloqueada
0–10 hours:
Avoid continuous operation above half throttle. Al-
low a cooling off period of five to ten minutes after
every hour of operation. Vary the speed of the ma-
chine from time to time. Do not operate it at one
set throttle position.
10–20 hours:
Avoid prolonged operation above 3/4 throttle. Rev
the machine freely through the gears but do not
use full throttle at any time.
After break-in:
Avoid prolonged full throttle operation. Vary
speeds occasionally.
EBU02111
Parking
When parking, stop the engine and shift into first
gear. Turn the fuel cock to “OFF” and apply the
parking brake.
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6-25
EBU02201
Parking on a slope
WARNING
_ Avoid parking on hills or other inclines. Park-
ing on a hill or other incline could cause the
ATV to roll out of control, increasing the
chance of an accident. If you must park on an
incline, put the ATV in low gear, apply the park-
ing brake, and block the front and rear wheels
with rocks or other objects. Do not park the
ATV at all on hills that are so steep you could
not walk up them easily. _1. Bring the ATV to a stop by applying the
brakes in low gear.
2. Stop the engine.
3. With the rear brake lever and brake pedal ap-
plied, apply the parking brake and slowly re-
lease the brake pedal.
U1P060.book Page 25 Monday, August 2, 2004 12:19 PM