Yamaha WR250F 2008 Owner's And Service Manual page 25

The engine fails to start
Pull the hot starter lever all the way
out and while holding the lever, kick
the kickstarter crank 10 to 20 times to
clear the engine. Then, restart the en-
gine. Refer to "Restarting an engine
after a fall".
Thro
ttle
grip
op-
era-
tion*
Ope
Air tempera-
n 3
ture = less
or 4
than 5 °C (41
time
°F)
St
s
ar
Air tempera-
ti
ture = more Non
n
than 5 °C (41 e
g
°F)
a
c
Air tempera-
ol
ture (normal
d
temperature)
Non
e
= between 5
e
n
°C (41 °F)
gi
and 25 °C
n
(77 °F)
e
Air tempera-
ture = more Non
than 25 °C e
(77 °F)
Starting an en-
Non
gine after a long
e
period of time
Restarting a Non
warm engine e
Restarting an en- Non
gine after a fall e
* Operate the throttle grip before kick
starting.
Observe the following break-in
procedures during initial operation
to ensure optimum performance
and avoid engine damage.
BREAK-IN PROCEDURES
1. Before starting the engine, fill the
fuel tank with the fuel.
2. Perform the pre-operation checks
on the machine.
3. Start and warm up the engine.
Check the idle speed, and check
the operation of the controls and
the engine stop switch. Then, re-
start the engine and check its op-
eration within no more than 5
minutes after it is restarted.
4. Operate the machine in the lower
gears at moderate throttle open-
ings for five to eight minutes.
5. Check how the engine runs when
the machine is ridden with the
throttle 1/4 to 1/2 open (low to me-
dium speed) for about one hour.
6. Restart the engine and check the
operation of the machine through-
Cold Hot
out its entire operating range. Re-
start- start-
start the machine and operate it
er er le-
for about 10 to 15 more minutes.
knob ver
The machine will now be ready to
race.
ON OFF
• After the break-in or before each
race, you must check the entire
machine for loose fittings and
fasteners as per "TORQUE-
CHECK POINTS". Tighten all
ON OFF
such fasteners as required.
• When any of the following parts
have been replaced, they must
be broken in.
CYLINDER AND CRANKSHAFT:
ON/
OFF
About one hour of break-in oper-
OFF
ation is necessary.
PISTON, RING, VALVES, CAM-
SHAFTS AND GEARS:
These parts require about 30
minutes of break-in operation at
OFF OFF
half-throttle or less. Observe the
condition of the engine carefully
during operation.
ON OFF
OFF ON
OFF ON
STARTING AND BREAK-IN
1-15