
TABLE OF CONTENTS
LOCATION OF IMPORTANT
LABELS ............................................1-1
SAFETY INFORMATION .................. 2-1
DESCRIPTION .................................. 3-1
Left view .......................................... 3-1
Right view ........................................ 3-2
Controls and instruments ................3-3
INSTRUMENT AND CONTROL
FUNCTIONS....................................... 4-1
Handlebar switch ............................ 4-1
Speed limiter and power reduction
plate ............................................4-1
Front brake lever ............................ 4-2
Rear brake lever ............................. 4-3
Fuel tank cap .................................. 4-3
Fuel ................................................ 4-3
Fuel tank breather hose ................. 4-5
2-stroke engine oil ..........................4-5
Fuel cock ........................................ 4-6
Starter (choke) lever ....................... 4-6
Kickstarter ......................................4-7
Seat ................................................ 4-7FOR YOUR SAFETY –
PRE-OPERATION CHECKS............. 5-1
OPERATION AND IMPORTANT
RIDING POINTS................................ 6-1
Starting and warming up a cold
engine ......................................... 6-1
Starting a warm engine .................. 6-1
Starting off ..................................... 6-2
Acceleration and deceleration ....... 6-2
Braking ........................................... 6-2
Engine break-in .............................. 6-3
Parking ........................................... 6-4
PERIODIC MAINTENANCE AND
ADJUSTMENT................................... 7-1
Owner’s tool kit .............................. 7-2
Periodic maintenance chart for the
emission control system ............. 7-3
General maintenance and
lubrication chart .......................... 7-4
Checking the spark plug ................ 7-6
Removing the power reduction
plate ............................................ 7-7
Transmission oil ............................. 7-8
Middle and final gear cases ........... 7-9
Cleaning the air filter element ........ 7-9
Cleaning the spark arrester ......... 7-10
Adjusting the carburetor ............... 7-11
Adjusting the engine idling
speed ........................................ 7-11Checking the throttle cable free
play ........................................... 7-12
Tires ............................................. 7-12
Panel wheels ................................ 7-13
Adjusting the front and rear brake
lever free play ........................... 7-14
Checking the front and rear brake
shoes ........................................ 7-15
Checking and lubricating the
cables ....................................... 7-15
Checking and lubricating the
throttle grip and cable ............... 7-16
Adjusting the Autolube pump ....... 7-16
Lubricating the front and rear
brake levers .............................. 7-16
Checking and lubricating the
centerstand ............................... 7-17
Checking the front fork ................. 7-17
Checking the steering .................. 7-18
Checking the wheel bearings ....... 7-18
Front wheel .................................. 7-18
Rear wheel ................................... 7-20
Troubleshooting ........................... 7-23
Troubleshooting chart .................. 7-24
MOTORCYCLE CARE AND
STORAGE.......................................... 8-1
Matte color caution ......................... 8-1
Care ............................................... 8-1
Storage ........................................... 8-3
U5PG8AE0.book Page 1 Thursday, April 8, 2010 8:37 AM

DESCRIPTION
3-1
3
EAU10410
Left view
1
2
3
45
6
1. Spark plug (page 7-6)
2. Fuel cock (page 4-6)
3. Throttle stop screw (page 7-11)
4. Air filter element (page 7-9)
5. Kickstarter (page 4-7)
6. Centerstand (page 7-17)U5PG8AE0.book Page 1 Thursday, April 8, 2010 8:37 AM

INSTRUMENT AND CONTROL FUNCTIONS
4-6
4
EAU40701
Fuel cock The fuel cock supplies fuel from the
tank to the carburetor while filtering it al-
so.
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 running.O (on)
With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
EAU13590
Starter (choke) lever“” Starting a cold engine requires a richer
air-fuel mixture, which is supplied by
the starter (choke).
Move the lever in direction (a) to turn on
the starter (choke).
Move the lever in direction (b) to turn off
the starter (choke).
1. Arrow mark pointing to “S” (stop)
1
1. Arrow mark pointing to “O” (on)
1
1. Starter (choke) lever“”
1 (a)
(b)
U5PG8AE0.book Page 6 Thursday, April 8, 2010 8:37 AM

SPECIFICATIONS
9-1
9
Dimensions:Overall length:
1245 mm (49.0 in)
Overall width:
575 mm (22.6 in)
Overall height:
715 mm (28.1 in)
Seat height:
485 mm (19.1 in)
Wheelbase:
855 mm (33.7 in)
Ground clearance:
105 mm (4.13 in)
Minimum turning radius:
1300 mm (51.2 in)Weight:With oil and fuel:
39 kg (86 lb)Noise and vibration level:Noise level (77/311/EEC):
PW50 75.1 dB(A)@2750 r/min
Vibration on seat (EN1032, ISO5008):
PW50 Will not exceed 0.5 m/s²
Vibration on handlebar (EN1032, ISO5008):
PW50 Will not exceed 2.5 m/s²Engine:Engine type:
Air cooled 2-stroke
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
49 cm³
Bore × stroke:
40.0 × 39.2 mm (1.57 × 1.54 in)Compression ratio:
6.00 :1
Starting system:
Kickstarter
Lubrication system:
Separate lubrication (Yamaha autolube)
Engine oil:Type:
YAMALUBE 2S or 2-stroke engine oil
(JASO FC grade) or (ISO EG-C or EG-D
grade)
Engine oil quantity:
Quantity:
0.30 L (0.32 US qt, 0.26 Imp.qt)Transmission oil:Type:
YAMALUBE 4 (10W-40) or SAE 10W-40
Oil change quantity:
0.30 L (0.32 US qt, 0.26 Imp.qt)Air filter:Air filter element:
Wet elementFuel:Recommended fuel:
PW50 Regular unleaded gasoline only
PW50A1 Regular unleaded gasoline only
(CAN)
PW50A1 Unleaded gasoline only
(AUS)(NZL)
Fuel tank capacity:
2.0 L (0.53 US gal, 0.44 Imp.gal)Carburetor:Type × quantity:
VM12SC x 1
Spark plug(s):Manufacturer/model:
NGK/BPR4HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)Clutch:Clutch type:
Wet, centrifugal automaticTransmission:Primary reduction system:
Spur gear
Primary reduction ratio:
63/33 (1.909)
Secondary reduction system:
Shaft drive
Secondary reduction ratio:
19/15 × 54/11 (6.218)Chassis:Frame type:
Steel tube backbone
Caster angle:
25.50 °
Trail:
50.0 mm (1.97 in)Front tire:Type:
With tube
Size:
2.50-10 4PR
Manufacturer/model:
BRIDGESTONE/KNOBBY
Manufacturer/model:
IRC/KNOBBY
U5PG8AE0.book Page 1 Thursday, April 8, 2010 8:37 AM

INDEXAAcceleration and deceleration................. 6-2
Air filter element, cleaning....................... 7-9
Autolube pump, adjusting ..................... 7-16BBrake lever, front..................................... 4-2
Brake lever, rear ..................................... 4-3
Brake levers, lubricating........................ 7-16
Brake shoes, checking .......................... 7-15
Braking .................................................... 6-2CCables, checking and lubricating .......... 7-15
Carburetor, adjusting ............................ 7-11
Care ........................................................ 8-1
Centerstand, checking and
lubricating ........................................... 7-17EEngine break-in ....................................... 6-3
Engine idling speed............................... 7-11
Engine oil ................................................ 4-5
Engine, starting a warm .......................... 6-1
Engine stop switch .................................. 4-1FFront and rear brake lever free play,
adjusting ............................................. 7-14
Front fork, checking .............................. 7-17
Fuel ......................................................... 4-3
Fuel cock................................................. 4-6
Fuel tank breather hose .......................... 4-5
Fuel tank cap .......................................... 4-3HHandlebar switch .................................... 4-1IIdentification numbers ........................... 10-1
KKickstarter............................................... 4-7LLabels, location....................................... 1-1MMaintenance and lubrication, periodic .... 7-4
Maintenance, emission control system... 7-3
Matte color, caution ................................ 8-1
Middle and final gear cases .................... 7-9
Model label ........................................... 10-1PParking ................................................... 6-4
Part locations .......................................... 3-1
Power reduction plate, removing ............ 7-7SSafety information................................... 2-1
Seat ........................................................ 4-7
Spark arrester, cleaning ....................... 7-10
Spark plug, checking .............................. 7-6
Specifications ......................................... 9-1
Speed limiter and power reduction
plate ..................................................... 4-1
Starter (choke) lever ............................... 4-6
Starting and warming up a cold
engine .................................................. 6-1
Starting off .............................................. 6-2
Steering, checking ................................ 7-18
Storage ................................................... 8-3TThrottle cable free play, checking ......... 7-12
Throttle grip and cable, checking and
lubricating ........................................... 7-16
Tires...................................................... 7-12
Tool kit .................................................... 7-2Transmission oil ...................................... 7-8
Troubleshooting .................................... 7-23
Troubleshooting chart ........................... 7-24
VVehicle Emission Control Information
label (For Canada) .............................. 10-2
Vehicle identification number ................ 10-1WWheel bearings, checking ..................... 7-18
Wheel (front) ......................................... 7-18
Wheel (rear) .......................................... 7-20
Wheels .................................................. 7-13
U5PG8AE0.book Page 1 Thursday, April 8, 2010 8:37 AM