2003 YAMAHA TTR125 check engine

SPEC
2 - 22
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each ride.Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Bead stopper M8 × 1.25 1 3 0.3 2.2
Driven sprocket (nut) M10 × 1.25 4 43 4.3 31
Driven sprocket (stud) M10 × 1.25 4 30 3.0 22
Sidestand mounting (nut) M10 × 1.25 1 44 4.4 32
Engine mounting:
Engine bracket (front) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (front) and engine M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and cylinder head M8 × 1.25 1 40 4.0 29
Engine and frame (rear) M8 × 1.25 2 40 4.0 29
Pivot shaft and nut M12 × 1.25 1 53 5.3 38
Relay arm and swingarm M12 × 1.25 1 53 5.3 38
Relay arm and connecting arm M10 × 1.25 1 35 3.5 25
Connecting arm and frame M10 × 1.25 1 35 3.5 25
Rear shock absorber assembly and frame M12 × 1.25 1 53 5.3 38
Rear shock absorber assembly and relay arm M10 × 1.25 1 35 3.5 25
Rear shock absorber and locknut (preload) M46 × 1.5 1 42 4.2 30
Drive chain tensioner (upper) M8 × 1.25 1 23 2.3 17
Drive chain tensioner (lower) M6 × 1.0 1 7 0.7 5.1
Drive chain support and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guide and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guard mounting M6 × 1.0 2 7 0.7 5.1
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender mounting M6 × 1.0 4 7 0.7 5.1
Flap guard mounting M6 × 1.0 2 4 0.4 2.9
Left side cover mounting M6 × 1.0 2 7 0.7 5.1
Seat mounting M6 × 1.0 2 7 0.7 5.1

3 - 1
INSP
ADJ
MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
*Fuel lineCheck fuel hoses for cracks or damage.
Replace if necessary.
Spark plugCheck condition.
Clean, regap or replace if necessary.
*ValvesCheck valve clearance.
Adjust if necessary.
Air filter Clean or replace element if necessary.
*CarburetorCheck engine idling speed and starter operation.
Adjust if necessary.
Exhaust systemsCheck for leakage.
Retighten if necessary.
Replace gasket if necessary.
Engine oilCheck oil level and vehicle for oil leakage.
Correct if necessary.
Change. (Warm engine before draining.)
ClutchCheck operation.
Adjust or replace cable.
*Front brakeCheck operation.
Adjust brake lever free play.
Check fluid level and leakage. (TT-R125LW only)Every ride
*Rear brakeCheck operation.
Adjust brake pedal free play and replace brake
shoes if necessary.Every ride
*WheelsCheck balance, runout, spoke tightness and for
damage.
Tighten spokes and rebalance, replace if
necessary.
*TiresCheck tread depth and for damage.
Replace if necessary.
Check air pressure.
Correct if necessary.
*Wheel bearingsCheck bearing for looseness or damage.
Replace if necessary.
*SwingarmCheck swingarm pivoting point for play.
Correct if necessary.
Lubricate with molybdenum disulfide grease.
Drive chainCheck chain slack.
Adjust if necessary. Make sure that the rear wheel
is properly aligned.
Clean and lubricate.Every ride
*Steering bearingsCheck bearing play and steering for roughness.
Correct accordingly.
Lubricate with lithium soap base grease every 120
hours.
SidestandCheck operation.
Lubricate and repair if necessary.

3 - 3
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation or practice, make sure the machine is in good operating condi-
tion.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-12
Engine oilCheck that the oil level is correct. Check the crankcase for leak-
age.P.3-7 ~ 10
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-4
Throttle grip/housingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-4 ~ 5
BrakesCheck the play of front and rear brake and effect of front and
rear brake.
Check fluid level and leakage. (TT-R125LW only)P.3-15 ~ 20
Drive chainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-21 ~ 22
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-24 ~ 25
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-25 ~ 27
Front forks and rear shock
absorber assemblyCheck that they operate smoothly and there is no oil leakage. P.3-23 ~ 24
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks. P.4-2
Sprocket Check that the driven sprocket tightening nut is not loose. P.3-20
Lubrication Check for smooth operation. Lubricate if necessary. P.3-28
Bolts and nuts Check the chassis and engine for loose bolts and nuts.—
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-5

3 - 4
INSP
ADJENGINE/CLUTCH ADJUSTMENT/
THROTTLE CABLE ADJUSTMENT
EC350000
ENGINE
CLUTCH ADJUSTMENT
1. Check:
Clutch lever free play a
Out of specification → Adjust.
Clutch lever free play a:
10 ~ 15 mm (0.39 ~ 0.59 in)
2. Adjust:
Clutch lever free play
NOTE:
Make minute adjustment on the lever side.
After adjustment, check proper operation of
clutch lever. Clutch lever free play adjustment steps:
Loosen the locknut 1.
Turn the adjuster 2 until free play a is
within the specified limits.
Tighten the locknut.
EC35A001
THROTTLE CABLE ADJUSTMENT
1. Check:
Throttle grip free play a
Out of specification → Adjust.
Throttle grip free play a:
3 ~ 5 mm (0.12 ~ 0.20 in)
2. Adjust:
Throttle grip free play
Throttle grip free play adjustment steps:
Loosen the locknut 1.
Turn the adjuster 2 until the specified free
play is obtained.
Tighten the locknut.

3 - 8
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
4. Check:
Oil 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:
Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
Do not allow foreign material to enter the
crankcase.
Recommended oil:
At –10 ˚C (10 ˚F) or higher Å:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
At 5 ˚C (40 ˚F) or higher ı:
Yamalube 4 (20W-40) or SAE
20W-40 type SE motor oil
(Except for USA and CDN)
CAUTION:
Do not add any chemical additives or use
oils with a grade of CD a or higher.
Do not use oils labeled “ENERGY CON-
SERVING II” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
Do 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 - 9
INSP
ADJ
ENGINE OIL REPLACEMENT
5. Install:
Dipstick
6. Start the engine and let it warm up for
several minutes.
7. Turn off the engine and inspect the oil
level once again.
NOTE:
Wait a few minutes until the oil settles before
inspecting the oil level.
ENGINE OIL REPLACEMENT
1. Start the engine and warm it up for sev-
eral minutes and wait for five minute.
2. Place the machine on a level place and
hold it on upright position by placing the
suitable stand under the engine.
3. Place a suitable container under the
engine.
4. Remove:
Oil drain bolt 1
Dipstick 2
Drain the engine oil.
5. Install:
Copper washer
Oil drain bolt 1
New
T R..20 Nm (2.0 m · kg, 14 ft · lb)
6. Fill:
Engine oil
7. Check:
Oil leakage
8. Check:
Engine oil level
9. Install:
Dipstick 2
Oil capacity:
Periodic oil change:
1.0 L (0.88 Imp qt, 1.06 US qt)

3 - 10
INSP
ADJOIL PRESSURE INSPECTION/PILOT AIR SCREW
ADJUSTMENT/ENGINE IDLING SPEED ADJUSTMENT
OIL PRESSURE INSPECTION
1. Check:
Oil pressure
Checking steps:
Slightly loosen the oil pressure check bolt
1.
Start 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.
Check oil passages and oil pump for dam-
age or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten 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:
Pilot 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.
Screw in the pilot air screw until it is lightly
seated.
Back 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:
Inductive tachometer
To spark plug lead.
3. Adjust:
Engine idling speed

3 - 11
INSP
ADJ
VALVE CLEARANCE INSPECTION AND ADJUSTMENT
VALVE CLEARANCE INSPECTION AND
ADJUSTMENT
NOTE:
The valve clearance should be adjusted
when the engine is cool to the touch.
The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
Seat
Fuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4. Adjustment steps:
Adjust the pilot air screw.
Refer to “PILOT AIR SCREW ADJUST-
MENT” section.
Turn the throttle stop screw 1 until the
specified engine idling speed.
To increase idling speed →
Turn the throttle stop screw 1 in a.
To decrease idling speed →
Turn the throttle stop screw 1 out b.
Inductive tachometer:
YU-8036-B/90890-03113
Engine idling speed:
1,300 ~ 1,500 r/min
2. Remove:
Spark plug
Intake tappet cover 1
Exhaust tappet cover 2
O-ring
3. Remove:
Timing mark accessing screw 1
Crankshaft end accessing screw 2
O-ring