2017 YAMAHA YS125 oil type

Periodic maintenance an d a djustment
6-12
6
ficiently
before removin g the oil
filler cap.
[EWA17640]
NOTICE: Do not
operate the vehicle until you
know that the en gine oil level is
sufficient.
[ECA10012]
TIPThe engine oil should be between the
minimum and maximum level marks.4. If the engine oil is below the mini- mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
5. Check the O-ring for damage, and replace it if necessary.
6. Install and tighten the engine oil filler cap.
To chan ge the en gine oil (with or
without oil filter element replace-
ment) 1. Start the engine, warm it up for several minutes, and then turn it
off.
2. Place an oil pan under the engine to collect the used oil.
3. Remove the engine oil filler cap, the engine oil drain bolt and its
gasket to drain the oil from the
crankcase.
TIPSkip steps 4–6 if the oil filter element is
not being replaced.4. Remove the oil filter element coverby removing the bolts.
1. Engine oil filler cap
1. O-ring
2. Engine oil dipstick
3. Maximum level mark
4. Minimum level mark
1
4 321
1. Engine oil drain bolt
2. Gasket
1. Bolt
2. Oil filter element cover
12
1
2
UBT4E0E0.book Page 12 Thursday, November 17, 2016 10:55 AM

Periodic maintenance an d a djustment
6-23
6 
Insufficient brake flui d may al-
low air to enter the b rake sys-
tem, re ducin g brakin g
performance.
 Clean the filler cap before re-
moving . Use only DOT 4 b rake
flui d from a seale d container.
 Use only the specified b rake flu-
i d ; otherwise, the ru bber seals
may deteriorate, causin g leak-
a g e.
 Refill with the same type of
brake flui d. A ddin g a brake flui d
other than DOT 4 may result in a
harmful chemical reaction.
 Be careful that water does not
enter the brake flui d reservoir
when refillin g. Water will si gnifi-
cantly lower the boilin g point of
the flui d an d may result in vapor
lock.
NOTICE
ECA17641
Brake flui d may damag e painted
surfaces or plastic parts. Always
clean up spille d flui d imme diately.
As the brake pads wear, it is normal for
the brake fluid level to gradually go
down. A low brake fluid level may indi-
cate worn brake pads and/or brake
system leakage; therefore, be sure to
check the brake pads for wear and the
brake system for leakage. If the brake
fluid level goes down suddenly, have a
Yamaha dealer check the cause before further riding.
EAU22724
Chan gin g the brake flui d Have a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and lubrica-
tion chart. In addition, have the oil seals
of the brake master cylinder and cali-
per as well as the brake hose replaced
at the intervals listed below or whenev-
er they are damaged or leaking.
 Oil seals: Replace every two
years.
 Brake hose: Replace every four
years.
UBT4E0E0.book Page 23 Thursday, November 17, 2016 10:55 AM

Periodic maintenance an d a djustment
6-33
6
EAU78872
Replacin g the hea dlig ht bul bThis model is equipped with a halogen
bulb headlight. If the headlight bulb
burns out, replace it as follows.NOTICE
ECA10651
Take care not to d amage the follow-
in g parts:
 Hea dlig ht bul b
Do not touch the g lass part of
the hea dlig ht bul b to keep it free
from oil, otherwise the transpar-
ency of the glass, the luminosity
of the b ulb, an d the bul b life will
b e ad versely affected . Thor-
ou ghly clean off any dirt an d fin-
g erprints on the head lig ht bul b
usin g a cloth moistened with al-
cohol or thinner.
 Hea dlig ht lens
Do not affix any type of tinted
film or stickers to the hea dlig ht
lens.
Do not use a hea dlig ht bul b of a
watta ge hi gher than specifie d.
1. Remove the headlight unit side
covers by removing the screw on
each side. 2. Remove the bolt on each side.
3. Loosen the headlight unit stay
bolt, and then tilt the headlight unit
forward.1. Do not touch the glass part of the bulb.
1. Headlight unit side cover
2. Screw
1
2
1. Headlight unit side cover
2. Screw
3. Headlight unit stay bolt
1. Bolt
213
1
UBT4E0E0.book Page 33 Thursday, November 17, 2016 10:55 AM

Specifications
8-1
8
Dimensions:Overall length:2005 mm (78.9 in)
Overall width:
735 mm (28.9 in)
Overall height: 1050 mm (41.3 in)
Seat height: 795 mm (31.3 in)
Wheelbase:
1320 mm (52.0 in)
Ground clearance: 150 mm (5.91 in)
Minimum turning radius: 2.2 m (7.22 ft)Wei ght:Curb weight:
129 kg (284 lb)Engine:Combustion cycle:
4-stroke
Cooling system: Air cooled
Valve train: SOHC
Number of cylinders:
Single cylinder
Displacement: 125 cm³
Bore × stroke:
52.4 × 57.9 mm (2.06 × 2.28 in)
Compression ratio:
10.0 : 1 Starting system:
Electric starter
Lubrication system: Wet sump
Engine oil:Recommended brand:
YAMALUBE
SAE viscosity grades: 10W-40, 20W-40
Recommended engine oil grade: API service SG type or higher, JASO
standard MA
Engine oil quantity:
Oil change:1.00 L (1.06 US qt, 0.88 Imp.qt)
With oil filter removal:
1.10 L (1.16 US qt, 0.97 Imp.qt)Air filter:Air filter element:Dry element
Fuel:Recommended fuel:Regular unleaded gasoline (Gasohol [E10]
acceptable)
Fuel tank capacity: 14 L (3.7 US gal, 3.1 Imp.gal)
Fuel reserve amount:
2.2 L (0.58 US gal, 0.48 Imp.gal)Fuel injection:Throttle body:ID mark:BT41 00Spark plu g(s):Manufacturer/model:
NGK/CPR8EA-9
Spark plug gap: 0.8–0.9 mm (0.031–0.035 in)Clutch:Clutch type:
Wet, multiple-discDrivetrain:Primary reduction ratio:3.409 (75/22)
Final drive:
Chain
Secondary reduction ratio: 3.071 (43/14)
Transmission type: Constant mesh 5-speed
Gear ratio:
1st:2.714 (38/14)
2nd:
1.789 (34/19)
010305070 90110
130 ˚F
-20 -10 0 10 20 3040
50 ˚C
SAE 10W-40
SAE 20W-40
UBT4E0E0.book Page 1 Thursday, November 17, 2016 10:55 AM

Specifications
8-2
8
3rd:1.318 (29/22)
4th: 1.045 (23/22)
5th:
0.875 (21/24)
Chassis:Frame type:Diamond
Caster angle:
25.0 °
Trail: 82 mm (3.2 in)Front tire:Type:
Tubeless
Size: 2.75-18M/C 42P
Manufacturer/model: CHENG SHIN/C910Rear tire:Type:Tubeless
Size: 100/80-18M/C 59P
Manufacturer/model:
CHENG SHIN/C905Loading:Maximum load:171 kg (377 lb)
(Total weight of rider, passenger, cargo
and accessories)
Tire air pressure (measured on cold
tires):1 person:
Front: 175 kPa (1.75 kgf/cm², 25 psi)
Rear:
200 kPa (2.00 kgf/cm², 29 psi)
2 persons: Front:
175 kPa (1.75 kgf/cm², 25 psi)
Rear: 225 kPa (2.25 kgf/cm², 33 psi)
Maximum load: Front: 175 kPa (1.75 kgf/cm², 25 psi)
Rear: 250 kPa (2.50 kgf/cm², 36 psi)Front wheel:Wheel type:Cast wheel
Rim size: 18M/C x MT1.85Rear wheel:Wheel type:Cast wheel
Rim size: 18M/C x MT2.15Unified brake system:Operation:Activated by front brakeFront brake:Type:
Hydraulic single disc brake Specified brake fluid:
DOT 3 or 4
Rear brake:Type:
Mechanical leading trailing drum brakeFront suspension:Type:Telescopic fork
Spring:
Coil spring
Shock absorber: Hydraulic damper
Wheel travel: 120 mm (4.7 in)Rear suspension:Type:Swingarm
Spring: Coil spring
Shock absorber:
Hydraulic damper
Wheel travel: 112 mm (4.4 in)Electrical system:System voltage:
12 V
Ignition system: TCI
Charging system: AC magnetoBattery:Model:YTX5L-BS
UBT4E0E0.book Page 2 Wednesday, December 21, 2016 11:07 AM