2005 YAMAHA YZ125LC gas type

1-12
GEN
INFO
FUEL AND ENGINE MIXING OIL
EC160051
FUEL AND ENGINE MIXING OIL
Mix oil with the gas at the ratio specified below.
Always use fresh, name-brand gasoline, and mix
the oil and gas the day of the race. Do not use
premix that is more than a few hours old.
NOTE:
If knocking or pinging occurs, use a different
brand of gasoline or higher octane grade.
cC
Never mix two types of oil in the same
batch; clotting of the oil could result. If you
wish to change oil types, be sure to drain
the fuel tank and the carburetor float bowl
of old premix prior to filling with the new
type.
Fuel tank capacity:
8.0 L (1.76 Imp gal, 2.11 US gal)
Mixing oil
Recommended oil:
Yamalube “2-R”
(Yamalube racing 2-cycle oil)
Mixing ratio: 30 : 1
If unavailable, use an equivalent
type of oil.
Recommended fuel:
Premium unleaded gasoline
only with a research octane
number of 95 or higher.
1C3-9-30-1B 14/5/04 5:03 PM Page 2

1-12
GEN
INFO
ESSENCE ET HUILE DE MELANGE DU MOTEUR
KRAFTSTOFF UND MOTORGEMISCHÖL
CARBURANTE E OLIO PER MISCELA PER MOTORI
KRAFTSTOFF UND
MOTORGEMISCHÖL
Öl im nachfolgend angegebenen Ver-
hältnis dem Kraftstoff beimengen.
Immer frischen Marken-Kraftstoff ver-
wenden und das Öl erst am Renntage
dem Kraftstoff beimengen. Niemals
ein Kraftstoff/Öl-Gemisch verwenden,
das mehr als einige Stungen alt ist.
ESSENCE ET HUILE DE
MELANGE DU MOTEUR
Mélanger le carburant à l’huile dans les
proportions indiquées ci-dessous. Utili-
ser systématiquement de l’essence
neuve et connue, mélanger l’huile et
l’essence le jour de la course. Eviter
l’emploi d’un mélange dont la prépara-
tion remonte à plus de quelques heures.
HINWEIS:
Falls es zu Zündfunkenklopfen
kommt, eine andere Benzin-Marke
oder Benzin mit einer höheren Oktan-
zahl verwenden.
dD
Niemals zwei verschiedene Ölsor-
ten zusammenmischen. Es kann zu
Ölklumpenbildung führen. Falls Sie
die Ölsorten wechseln möchten,
unbedingt zuvor den Kraftstoff-
behälter und die Vergaserschwim-
merkammer entleeren, bevor die
neue Ölsorte eingefüllt wird.
N.B.:
Si un cognement ou un cinglement sur-
vient, utiliser une marque d’essence dif-
férente ou une classe d’octane supérieu-
re.
ffF
Evitez de mélanger deux huiles diffé-
rentes dans le même mélange déssen-
ce, car elles pourraient se coaguler. Si
vous désirez changer d’huile, assu-
rez-vous de vider l’ancien mélange
contenu dans le réservoir et la cuve à
flotteur du carburant avant de verser
le nouveau.
IC160051
CARBURANTE E OLIO
PER MISCELA PER
MOTORI
Miscelare l’olio con la benzina nel rap-
porto specificato più sotto. Usare sem-
pre benzina fresca, di marca; e miscela-
re l’olio e la benzina il giorno della
gara. Non usare una miscela già prepa-
rata che abbia più di qualche ora.
NOTA:
Se si verifica detonazione o battito in
testa, usare una marca di benzina diver-
sa o una qualità con un numero di ottani
più alto.
iI
Non miscelare mai due tipi di olio
nella stessa miscela; potrebbe risul-
tarne un raggrumamento dell’olio. Se
si desidera cambiare tipo di olio, assi-
curarsi di scaricare la vecchia miscela
preparata dal serbatoio del carburan-
te e dalla vaschetta del carburatore
prima di riempirli con il nuovo tipo.
Huile de mélange
Huile préconisée:
Yamalube “2-R”
(Huile deux temps
Yamalube de course)
Proportions de
mélange: 30 : 1
Si indisponible, utilisez
une huile d’un type
équivalent.
Contenance du réservoir
d’essence:
8,0 L (1,76 Imp gal,
2,11 US gal)Capacità del serbatoio del
carburante:
8,0 L (1,76 Imp gal,
2,11 US gal)
Olio per miscela
Olio raccomandato:
Yamalube “2-R”
(Olio a 2 cicli per
corse Yamalube)
Rapporto di
miscelazioen: 30 : 1
Qualora non fosse
disponibile, utilizzare un
tipo d'olio equivalente.Mischöl
Empfohlenes Öl:
Yamalube „2-R“
(Yamalube Zwei-
takt-Rennöl)
Mischungsverhält-
nis: 30 : 1
Falls nicht verfügbar,
gleichwertigen Öltyp
wählen.
Kraftstofftank-
Fassungsvermögen:
8,0 L (1,76 lmp gal,
2,11 US gal)
Essence préconisée:
Essence super sans
plomb d’un indice
d’octane recherche
de 95 ou plus uni-
quement.Carburante
raccomandato:
Unicamente benzi-
na super senza
piombo con numero
di ottano research
95 e più.Empfohlenes Kraftstoff:
Nur bleifreies
Superbenzin mit
einer
Oktanzahl (Roz)
von 95 oder höher.
1C3-9-30-1B 14/5/04 5:03 PM Page 3

2-1
SPECGENERAL SPECIFICATIONS
Model name: YZ125T1 (USA, CDN)
YZ125 (EUROPE, ZA)
YZ125T (AUS, NZ)
Model code number: 1C31 (USA, CDN, ZA)
1C32 (EUROPE)
1C34 (AUS, NZ)
Dimensions:USA, ZAAUS, NZ EUROPE, CDN
Overall length 2,134 mm←2,139 mm
(84.0 in) (84.2 in)
Overall width 827 mm←←
(32.6 in)
Overall height 1,316 mm←1,318 mm
(51.8 in) (51.9 in)
Seat height 992 mm←994 mm
(39.1 in) (39.1 in)
Wheelbase 1,443 mm←←
(56.8 in)
Minimum ground clearance 387 mm 388 mm 389 mm
(15.2 in) (15.3 in) (15.3 in)
Dry weight:
Without oil and fuel 86.0 kg (189.6 lb)
Engine:
Engine type Liquid cooled 2-stroke, gasoline
Cylinder arrangement Single cylinder, forward inclined
Displacement 124 cm
3(4.36 lmp oz, 4.19 US oz)
Bore ×Stroke 54 ×54.5 mm (2.126 ×2.146 in)
Compression ratio 8.6~10.7 : 1
Starting system Kick starter
Lubrication system: Premix (30 : 1)(Yamalube 2-R)
Oil type or grade (2-Cycle):
Transmission oil Yamalube 4 (10W-30) or SAE 10W-30 type SE
motor oil
Periodic oil change 0.66 L (0.58 Imp qt, 0.69 US qt)
Total amount 0.70 L (0.62 Imp qt, 0.74 US qt)
Coolant capacity (including all routes): 0.9 L (0.79 Imp qt, 0.95 US qt)
Air filter: Wet type element
Fuel:
Type Premium unleaded gasoline
only with a research octane
number of 95 or higher
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
EC200000
SPECIFICATIONSEC211000
GENERAL SPECIFICATIONS
1C3-9-30-2A 25/5/04 7:13 PM Page 2

2-2
SPECGENERAL SPECIFICATIONS
Carburetor:
Type/Manufacturer TMXχ
38SS/MIKUNI
Spark plug:
Type/Manufacturer BR9EG/NGK (resistance type)
Gap 0.5~0.6 mm (0.020~0.024 in)
Clutch type: Wet, multiple-disc
Transmission:
Primary reduction system Gear
Primary reduction ratio 64/19 (3.368)
Secondary reduction system Chain drive
Secondary reduction ratio 48/13 (3.692)
Transmission type Constant mesh, 6-speed
Operation Left foot operation
Gear ratio: 1st 31/13 (2.385)
2nd 29/15 (1.933)
3rd 27/17 (1.588)
4th 23/17 (1.353)
5th 24/20 (1.200)
6th 23/21 (1.095)
Chassis:USA, ZA, AUS, NZEUROPE,CDN
Frame type Semi double cradle←
Caster angle 25.5° 25.6°
Trail 104 mm (4.09 in) 107 mm (4.21 in)
Tire:
Type With tube
Size (front) 80/100-21 51M
Size (rear) 100/90-19 57M
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm2, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/Gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
2
1C3-9-30-2A 25/5/04 7:13 PM Page 3

2-7
SPECMAINTENANCE SPECIFICATIONS
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing…
Front suspension: USA, CDN, ZA,
EUROPE
AUS, NZ
Front fork travel
300 mm (11.8 in)←…
Fork spring free length
465 mm (18.3 in)←460 mm (18.1 in)
Spring rate, STD K=4.1 N/mm K=4.0 N/mm…
(0.418 kg/mm, (0.408 kg/mm,
23.4 lb/in) 22.8 lb/in)
Optional spring/Spacer Yes←…
Oil capacity 430 cm
3435 cm3…
(15.1 Imp oz, (15.3 Imp oz,
14.5 US oz) 14.7 US oz)
Oil grade Suspension oil ←…
“S1”
Inner tube outer diameter 48 mm (1.89 in)←…
Front fork top end 5 mm (0.2 in)←…
Rear suspension: USA, CDN, ZA,
EUROPE
AUS, NZ
Shock absorber travel
132 mm (5.20 in)←…
Spring free length
260 mm (10.24 in)←…
Fitting length
252 mm (9.92 in)248 mm (9.76 in)…

240.5~258.5 mm←…
(9.47~10.18 in)
Spring rate, STD K=46.0 N/mm ←…
(4.70 kg/mm,
263.2 lb/in)
Optional spring Yes←…
Enclosed gas pressure 1,000 kPa ←…
(10 kg/cm
2,
142 psi)
Swingarm:
Swingarm free play limit
End…
1.0 mm (0.04 in)
Side clearance…
0.2~0.9 mm
(0.008~0.035 in)
1C3-9-30-2A 25/5/04 7:13 PM Page 8

2-7
SPECCARACTERISTIQUES D’ENTRETIEN
PARTIE-CYCLE
Article Standard Limite
Direction:
Type de roulement de direction Roulement à rouleaux conique…
Suspention avant: USA, CDN, ZA,
EUROPE
AUS, NZ
Débattement de fourche avant
300 mm (11,8 in)←…
Longueur libre de ressort de fourche
465 mm (18,3 in)←460 mm (18,1 in)
Course de ressort, STD K=4,1 N/mm K=4,0 N/mm…
(0,418 kg/mm, (0,408 kg/mm,
23,4 lb/in) 22,8 lb/in)
Ressort/entretoise optionnel Oui←…
Quantité d’huile 430 cm
3435 cm3…
(15,1 Imp oz, (15,3 Imp oz,
14,5 US oz) 14,7 US oz)
Grade d’huile Huile de ←…
suspension “S1”
Diamètre extérieur de tube interne 48 mm (1,89 in)←…
Extrémite supérieure de fourche avant 5 mm (0,2 in)←…
Suspension arrière: USA, CDN, ZA,
EUROPE
AUS, NZ
Débattement d’amortisseur
132 mm (5,20 in)←…
Longueur de ressort libre
260 mm (10,24 in)←…
Longueur de raccord
252 mm (9,92 in)248 mm (9,76 in)…

240,5~258,5 mm←…
(9,47~10,18 in)
Course de ressort, STD K=46,0 N/mm ←…
(4,70 kg/mm,
263,2 lb/in)
Ressort optionnel Oui←…
Pression de gas enfermé 1.000 kPa ←…
(10 kg/cm
2,
142 psi)
Bras oscillant:
Limite de jeu de bras oscillatnt
Extrémité…
1,0 mm (0,04 in)
Latéral…
0,2~0,9 mm
(0,008~0,035 in)
1C3-9-30-2A 25/5/04 7:13 PM Page 20

3-13
INSP
ADJ
TRANSMISSION OIL REPLACEMENT
3. Check:
9Transmission oil level
EC35K002
TRANSMISSION OIL REPLACEMENT
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 position by placing the suitable
stand under the engine.
3. Place a suitable container under the engine.
Transmission oil level checking steps:
9Remove the oil check bolt 1.
9Inspect the oil level.
NOTE:
Be sure the machine is positioned straight
up when inspecting the oil level.
w
Never attempt to remove the oil check bolt
just after high speed operation. The heat-
ed 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.
9Inspect the gasket (oil check bolt), replace if
damaged.
9Tighten the oil check bolt.
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil check bolt:
10 Nm (1.0 m•kg, 7.2 ft•lb)
1C3-9-30-3A 17/5/04 8:42 PM Page 34

3-38
ELECTRICAL/SPARK PLUG INSPECTION
INSP
ADJ
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
9Spark plug
2. Inspect:
9Electrode 1
Wear/Damage Replace.
9Insulator 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:
9Plug gap a
Use a wire gauge or thickness gauge.
Out of specification Regap.
4. Clean the plug with a spark plug cleaner if
necessary.
5. Tighten:
9Spark plug
NOTE:
9Before installing a spark plug, clean the
gasket surface and plug surface.
9Finger-tighten athe spark plug before torquing
to specification b.
Spark plug gap:
0.5~0.6 mm (0.020~0.024 in)
Standard spark plug:
BR9EG/NGK (resistance type)
20 Nm (2.0 m•kg, 14 ft•lb)
1C3-9-30-3B 17/5/04 1:22 PM Page 40