Yamaha yz250 2015, Owner'S Manual

Page: 53 / 174

3-9
ENGINE
Never attempt to remove the oil
check bolt just after high speed
operation. The heated oil could
spout out, causing danger. Wait
until the oil cools down.
Oil flows out → Oil level is correct.
Oil does not flow out
→
Oil level is
low. Add transmission oil until oil
flows out.
c. Inspect the gasket (oil check bolt),
replace if damaged.
d. Tighten the oil check bolt.
CHANGING THE TRANSMISSION
OIL
1. Start the engine and warm it up
for several minutes and wait for
five minute.
2. Place the machine on a level
place and hold it on upright posi-
tion by placing the suitable stand
under the engine.
3. Place a suitable container under
the engine.
4. Remove:
• Oil drain bolt "1"
• Oil filler cap "2"
Drain the transmission oil.
5. Install:
• Aluminum washer
• Oil drain bolt "1"
6. Fill:
• Transmission oil
7. Check:
• Oil leakage
8. Check:
• Transmission oil level
9. Install:
• Oil filler cap "2"
ADJUSTING THE PILOT AIR
SCREW
1. Adjust:
• Pilot air screw "1"
Adjustment steps:
a. Turn in the pilot air screw until it is
lightly seated.
b. Turn out the pilot air screw by the
factory-set number of turns.
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
air screw has been individually set at
the factory. Before adjusting the pilot
air screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Turn the throttle stop screw "1"
until the engine runs at the lowest
possible speed.
CHECKING THE EXHAUST PIPE
1. Inspect:
• O-ring "1"
Damage
→
Replace.
Install the O-rings with their de-
pressed "a" facing outward.
Recommended brand:
YAMALUBE
Recommended engine
oil type
SAE10W-40
Recommended engine
oil grade
API service SG type or
higher, JASO standard
MA
Oil check bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil drain bolt:
23 Nm (2.3 m•kg, 17
ft•lb)
Recommended brand:
YAMALUBE
Recommended engine
oil type
SAE10W-40
Recommended engine
oil grade
API service SG type or
higher,JASO standard
MA
Oil capacity (periodic oil
change):
0.75 L (0.66 Imp qt, 0.79
US qt)
Pilot air screw:
1-1/4 turns out
* 2-1/4 turns out
(for reference only)
* Except for USA and CDN
To increase idle speed → Turn the
throttle stop screw "1" in.
To decrease idle speed → Turn the
throttle stop screw "1" out.