
Instrument and control functions
4-6
4
EAU13454
2-stroke en gine oil
Make sure that there is sufficient 2-
stroke engine oil in the oil tank. Add the
recommended 2-stroke engine oil as
necessary.
NOTICE
ECA16671
Make sure that the 2-stroke en gine
oil tank cap is properly installe d.
EAU40702
Fuel cock
The fuel cock supplies fuel from the
tank to the carburetor while filtering it
also.
The fuel cock has two positions:
S (stop)
With the lever in this position, fuel will
not flow. Always return the lever to this
position when the engine is not run-
ning.
O (on)
With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
1. 2-stroke engine oil tank cap
2. Minimum level mark
Recommen ded  oil:
See page 9-1.
Oil quantity: 0.30 L (0.32 US qt, 0.26 Imp.qt)
2 1
1. Arrow mark pointing to “S” (stop)
1. Arrow mark pointing to “O” (on)
1
1
U2SA85E0.book  Page 6  Friday, May 11, 2018  9:07 AM 

For your safety – pre-operation checks
5-1
5
EAU63440
Inspect your vehicle each time you use it to make sure the vehicle is in safe oper-
ating condition. Always follow the inspection and maintenance procedures and
schedules described in the Owner’s Manual.
WARNING
EWA11152
Failure to inspect or maintain the vehicle properly increases the possibility
of an acci dent or equipment d amage. Do not operate the vehicle if you fin d
any prob lem. If a pro blem cannot  be corrected  b y the proce dures provi ded
in this manual, have the vehicle inspecte d b y a Yamaha d ealer.
Before using this vehicle, check the following points:
ITEM CHECKSPAGE
Fuel • Check fuel level in fuel tank.
• Refuel if necessary.
• Check fuel line for leakage.
• Check fuel tank breather hose for obstructions, cracks 
or damage, and check hose connection. 4-4, 4-5
2-stroke en gine oil • Check oil level in oil tank.
• If necessary, add recommended oil to specified level.
• Check vehicle for oil leakage. 4-6
Tr a n s m i s s i o n  o i l • Check oil level in transmission case.
• If necessary, add recommended oil to specified level. 7-8
Mi dd le an d final g ear 
cases • Check vehicle for grease leakage.
7-10
Front  brake • Check operation.
• Lubricate cable if necessary.
• Check lever free play.
• Adjust if necessary. 7-17, 
7-18
Rear  brake • Check operation.
• Lubricate cable if necessary.
• Check lever free play.
• Adjust if necessary. 7-17, 
7-18
Throttle g rip • Make sure that operation is smooth.
• Check throttle grip free play.
• If necessary, have Yamaha dealer adjust throttle grip 
free play and lubricate cable and grip housing. 7-14, 
7-19
Control ca bles • Make sure that operation is smooth.
• Lubricate if necessary.
7-19
Wheels an d tires •Check for damage.
• Check tire condition and tread depth.
• Check air pressure.
• Correct if necessary. 7-14, 
7-16
Brake levers • Make sure that operation is smooth.
• Lubricate lever pivoting points if necessary.
7-20
U2SA85E0.book  Page 1  Friday, May 11, 2018  9:07 AM 

Periodic maintenance an d a djustment
7-9
7
4. Install the transmission oil drain
bolt and its new gasket, and then
tighten the bolt to the specified
torque.
5. Refill with the specified amount of the recommended transmission
oil.
NOTICE
ECA10453
In or der to prevent clutch slip-
pa ge (since the transmission oil
also lu bricates the clutch),  do
not mix any chemical additives.
Do not use oils with a  diesel
specification of “CD” or oils of a
hi gher quality than specifie d. In
a ddition,  do not use oils la bele d
“ENERGY CONSERVING II” or
hi gher.
 Make sure that no forei gn mate-
rial enters the transmission.
6. Check the O-ring for damage, and replace it if necessary. 7. Install and tighten the transmis-
sion oil filler cap.
8. Start the engine, and then let it idle for several minutes while checking
the transmission for oil leakage. If
oil is leaking, immediately turn the
engine off and check for the cau-
se.
Tightening  torque:
Transmission oil drain bolt: 14 N·m (1.4 kgf·m, 10 lb·ft)
Recommen ded  transmission oil:
See page 9-1.
Oil chan ge quantity:
0.30 L (0.32 US qt, 0.26 Imp.qt)
1. O-ring
1
U2SA85E0.book  Page 9  Friday, May 11, 2018  9:07 AM 

Periodic maintenance an d a djustment
7-11
7
4. Apply oil of the recommended
type to the entire surface of the
sponge material, and then
squeeze the excess oil out.
TIP
The sponge material should be wet but
not dripping.
5. Insert the sponge material into theair filter case.  NOTICE: Make
sure that the spon ge material is
properly seated  in the air filter
case. The en gine shoul d never
b e operated  without the spon ge
material installe d, otherwise the
piston(s) an d/or cylin der(s) may
b ecome excessively worn.
[ECA15622]
6. Install the air filter case cover by
installing the screw.
7. Install the seat.
EAU41222
Cleanin g the spark arrester
The spark arrester should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
WARNING
EWA10981
 Always let the exhaust system
cool prior to touching  exhaust
components.
 Do not start the en gine when
cleanin g the exhaust system.
1. Remove the tailpipe by removing
the screw, and then pulling it out
of the muffler.
2. Tap the tailpipe lightly, and then use a wire brush to remove any
carbon deposits from the spark
arrester portion of the tailpipe and
inside of the tailpipe housing.
Recommen ded  oil:
Yamaha foam air filter oil or other 
quality foam air filter oil
1. Tailpipe
2. Screw
3. Muffler
1
2
3
U2SA85E0.book  Page 11  Friday, May 11, 2018  9:07 AM 

Specifications
9-1
9
Dimensions:
Overall length:1245 mm (49.0 in)
Overall width:
610 mm (24.0 in)
Overall height: 705 mm (27.8 in)
Seat height: 475 mm (18.7 in)
Wheelbase:
855 mm (33.7 in)
Ground clearance: 95 mm (3.74 in)
Minimum turning radius: 1.3 m (4.27 ft)
Wei ght:
Curb weight:
41 kg (90 lb)
Maximum rider weight: 25.0 kg (55 lb)
Technical permissible mass (Maximum load + 
Curb weight): 66 kg (146 lb)
Noise an d vi bration level:
Noise level (77/311/EEC):
75.1 dB(A) at 2750 r/min 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR)
Uncertainty of measurement:
3.0 dB(A) 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR)
Vibration on seat (EN1032, ISO5008):
Will not exceed 0.5 m/s² 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR)
Uncertainty of measurement:
0.1 m/s² 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR) Vibration on handlebar (EN1032, ISO5008):
Will not exceed 2.5 m/s² 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR)
Uncertainty of measurement: 0.4 m/s² 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR)
Engine:
Combustion cycle:
2-stroke
Cooling system: Air cooled
Number of cylinders:
Single cylinder
Displacement: 49 cm³
Bore  × stroke:
40.0  × 39.2 mm (1.57 ×  1.54 in)
Compression ratio:
6.0 : 1
Starting system: Kickstarter
Lubrication system: Separate lubrication
Engine oil:
Engine oil:
YAMALUBE 2S or 2-stroke engine oil 
(JASO FC grade or ISO EG-C [or EG-D] 
grade)
Recommended brand:
YAMALUBE
Engine oil quantity: Engine oil tank capacity:
0.30 L (0.32 US qt, 0.26 Imp.qt)
Transmission oil:
Type: Motor oil SAE 10W-30 type SE or higher or 
Gear oil SAE 85W GL-3
Quantity: 0.30 L (0.32 US qt, 0.26 Imp.qt)
Air filter:
Air filter element:Wet element
U2SA85E0.book  Page 1  Friday, May 11, 2018  9:07 AM 

Specifications
9-2
9
Fuel:
Recommended fuel:Regular unleaded gasoline only
Fuel tank capacity:
2.0 L (0.5 US gal, 0.4 Imp.gal)
Car buretor:
Type  × quantity:
VM12SC ×  1
Spark plug(s):
Manufacturer/model:
NGK/BP4HS (PW50_ZAF)
NGK/BPR4HS 
(PW50_AUT/BEL/CHE/CYP/CZE/DEU/DN
K/ESP/FIN/FRA/GBR/GRC/HRV/HUN/IRL
/ITA/NLD/NOR/POL/PRT/SVK/SVN/SWE/
TUR, PW50K, PW50K2)
Manufacturer/model: DENSO/W14FP-L (PW50_ZAF)
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Clutch:
Clutch type:Wet, centrifugal, shoe
Drivetrain:
Primary reduction ratio:1.909 (63/33)
Final drive: Shaft
Secondary reduction ratio:
6.218 (19/15 x 54/11)
Chassis:
Frame type:Backbone
Caster angle:
25.5 °
Trail: 50 mm (2.0 in)
Front tire:
Type:
With tube
Size: 2.50-10 4PR
Manufacturer/model: BRIDGESTONE/M29
Manufacturer/model:
IRC/Z MARK II (PW50_ZAF, PW50K, 
PW50K2)
Speed rating:
100 km/h (62 mph)
Rear tire:
Type:With tube
Size:
2.50-10 4PR
Manufacturer/model: BRIDGESTONE/M29
Manufacturer/model: IRC/Z MARK II (PW50_ZAF, PW50K, 
PW50K2)
Speed rating: 100 km/h (62 mph)
Tire air pressure (measure d on col d 
tires):
Front:
100 kPa (1.00 kgf/cm², 15 psi)
Rear: 100 kPa (1.00 kgf/cm², 15 psi)
Front wheel:
Wheel type:Panel wheel
Rim size: 10 x 1.50
Rear wheel:
Wheel type:Panel wheel
Rim size: 10 x 1.50
Front  brake:
Type:
Mechanical leading trailing drum brake
Rear  brake:
Type:
Mechanical leading trailing drum brake
Front suspension:
Type:Telescopic fork
Spring:
Coil spring
Shock absorber: Hydraulic damper
Wheel travel: 60 mm (2.4 in)
Rear suspension:
Type:Unit swing
Spring: Coil spring
Shock absorber:
Hydraulic damper
U2SA85E0.book  Page 2  Friday, May 11, 2018  9:07 AM