check engine light YAMAHA TTR125 2002 Owners Manual

1 - 13
GEN
INFO
STARTING AND BREAK-IN
EC190000
STARTING AND BREAK-IN
CAUTION:
Before starting the machine, perform the
checks in the pre-operation check list.
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
STARTING A COLD ENGINE
1. Shift the transmission into neutral.
2. Turn the fuel cock to “ON” and full open
the starter knob (CHOKE).
3. With the throttle completely closed start
the engine by kicking the kickstarter
crank forcefully with firm stroke.
4. Run the engine at idle or slightly higher
until it warms up: this usually takes about
one or two minutes.
5. The engine is warmed up when it
responds normally to the throttle with the
starter knob (CHOKE) turned off.
CAUTION:
Do not warm up the engine for extended
periods.
EC193001
STARTING A WARM ENGINE
Do not operate the starter knob (CHOKE).
Open the throttle slightly and start the engine
by kicking the kickstater forcefully with firm
stroke.
CAUTION:
Observe the following break-in procedures
during initial operation to ensure optimum
performance and avoid engine damage.

3 - 8
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
4. Check:
lOil level
Oil level should be between maximum
a and minimum b marks.
Oil level is low ® Add oil to proper
level.
NOTE:
When inspecting the oil level, do not screw the
dipstick into the oil tank. Insert the gauge
lightly.
(For USA and CDN)
CAUTION:
lDo not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
lDo not allow foreign material to enter the
crankcase.
Recommended oil:
At –10 ˚C (10 ˚F) or higher :
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
At 5 ˚C (40 ˚F) or higher õ:
Yamalube 4 (20W-40) or SAE
20W-40 type SE motor oil
(Except for USA and CDN)
CAUTION:
lDo not add any chemical additives or use
oils with a grade of CD a or higher.
lDo not use oils labeled “ENERGY CON-
SERVING II” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
lDo not allow foreign materials to enter the
crankcase.
Recommended oil:
Refer to the following chart for
selection of oils which are suited
to the atmospheric temperatures.
Recommended engine oil classi-
fication:
API STANDARD:
API “SE” or higher grade
(Designed primarily for motor-
cycles)

3 - 10
INSP
ADJOIL PRESSURE INSPECTION/PILOT AIR SCREW
ADJUSTMENT/ENGINE IDLING SPEED ADJUSTMENT
OIL PRESSURE INSPECTION
1. Check:
lOil pressure
Checking steps:
lSlightly loosen the oil pressure check bolt
1.
lStart the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt. If no oil comes out after one minute,
turn the engine off so it will not seize.
lCheck oil passages and oil pump for dam-
age or leakage.
lStart the engine after solving the prob-
lem(s) and recheck the oil pressure.
lTighten the oil pressure check bolt.
T R..
Oil pressure check bolt:
7 Nm (0.7 m • kg, 5.1 ft • lb)
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
lPilot air screw 1
Adjustment steps:
NOTE:
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.
lScrew in the pilot air screw until it is lightly
seated.
lBack out by the specified number of turns.
Pilot air screw:
2-1/2 ~ 3-1/2 turns out (example)
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
lInductive tachometer
To spark plug lead.
3. Adjust:
lEngine idling speed

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INSP
ADJ
ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
lSpark plug
2. Inspect:
lElectrode 1
Wear/damage ® Replace.
lInsulator color 2
Normal condition is a medium to light
tan color.
Distinctly different color ® Check the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
lPlug gap a
Use a wire gauge or thickness gauge.
Out of specification ® Regap.
4. Clean the plug with a spark plug cleaner
if necessary.
Spark plug gap:
0.6 ~ 0.7 mm (0.02 ~ 0.03 in)
Standard spark plug:
CR7HSA (NGK)
U22FSR-U (DENSO)
5. Tighten:
lSpark plug
NOTE:
lBefore installing a spark plug, clean the gas-
ket surface and plug surface.
lFinger-tighten a the spark plug before
torquing to specification b.
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)

4 - 67
ENGCRANKCASE, CRANKSHAFT AND BALANCER
REMOVAL POINTS
Crankcase
1. Remove:
lBolt (crankcase)
lLead guide 1
lClutch cable holder 2
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove them.
2. Remove:
lRight crankcase 1
Use the crankcase separating tool 2.
NOTE:
lFully tighten the tool holding bolts, but make
sure the tool body is parallel with the case. If
necessary, one screw may be backed out
slightly to level tool body.
lAs pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If one end “hangs
up”, take pressure off the push screw, re-
align, and start over. If the cases do not
separate, check for a remaining case screw
or fitting. Do not force.
Crankcase separating tool:
YU-1135-A/90890-01135