2004 YAMAHA WHY 50 transmission

2
DESCRIPTION
Left view
6
5 7
1234
1. Rear brake lever (page 3-5, 6-12, 6-15)
2. Fuel gauge (page 3-3)
3. Speedometer (page 3-3)
4. Main switch (page 3-1, 3-8)5. Final transmission oil filler cap (page 6-6)
6. Kick starter (page 3-7)
7. Air filter (page 6-7)
2-1

PRE-OPERATION CHECKS
4
•Check fuel level in fuel tank.
Fuel•Refuel if necessary. 3-5 — 3-6
•Check fuel line for leakage.
•Check oil level in oil tank.
2-stroke engine oil•If necessary, add recommended oil to specified level. 3-5 — 3-7
•Check vehicle for oil leakage.
Final transmission oil•Check vehicle for oil leakage. 6-6
•Check operation.
•If soft or spongy, have Yamaha dealer bleed hydraulic system.
Front brake•Check fluid level in reservoir. 3-5, 6-13 — 6-15
•If necessary, add recommended brake fluid to specified level.
•Check hydraulic system for leakage.
•Check operation.
Rear brake•Check pedal free play. 3-5, 6-13 — 6-15
•Adjust if necessary.
•Make sure that operation is smooth.
Throttle grip•Check cable free play.
6-9, 6-15
•If necessary, have Yamaha dealer adjust cable free play
and lubricate cable and grip housing.
The condition of a vehicle is the owner’s responsibility. Vital components can start to deteriorate quickly and unexpectedly,
even if the vehicle remains unused (for example, as a result of exposure to the elements). Any damage, fluid leakage or
loss of tire air pressure could have serious consequences. Therefore, it is very important, in addition to a thorough visual
inspection, to check the following points before each ride.
EAU03439
Pre-operation check list
ITEM CHECKS PAGE
4-1

OPERATION AND IMPORTANT RIDING POINTS
5
EAU00436
Engine break-in
There is never a more important period
in the life of your engine than the period
between 0 and 1,000 km. For this
reason, you should read the following
material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1,000 km. The various parts in the
engine wear and polish themselves to
the correct operating clearances.
During this period, prolonged full-
throttle operation or any condition that
might result in engine overheating must
be avoided.
EAUT0003*
0 — 150 km
Avoid operation above 1/3 throttle. Stop
the engine and let it cool for 5 to 10
minutes after every hour of operation.
Vary the speed of the scooter from time
to time. Do not operate it at one set
throttle position.150 — 500 km
Avoid prolonged operation above 1/2
throttle.
500 — 1,000 km
Avoid cruising speeds in excess of 3/
4 throttle.
ECAT0001
After 1,000 km of operation, be sure
to replace the final transmission oil.
1,000 km and beyond
Avoid prolonged full throttle operation.
Vary speeds occasionally.
EC000049
If any engine trouble should occur
during the engine break-in period,
immediately have a Yamaha dealer
check the vehicle.
EAU00461
Parking
When parking, stop the engine, and
then remove the key from the main
switch.
EW000058
•Since the engine and exhaust
system can become very hot,
park in a place where
pedestrians or children are not
likely to touch them.
•Do not park on a slope or on
soft ground, otherwise the
scooter may overturn.
EC000062
Never park in an area where there
are fire hazards such as grass or
other flammable materials.
5-4

EAU00462
PERIODIC MAINTENANCE AND MINOR REPAIR
Periodic maintenance and lubrication chart ............ 6-2
Removing and installing the panel .......................... 6-5
Panel A .................................................................... 6-5
Checking the spark plug ......................................... 6-5
Final transmission oil .............................................. 6-6
Cleaning the air filter element ................................. 6-7
Adjusting the carburetor .......................................... 6-9
Adjusting the throttle cable free play ....................... 6-9
Tires ...................................................................... 6-10
Cast wheels .......................................................... 6-11
Adjusting the front brake lever free play ................ 6-12
Adjusting the front brake lever free play ................ 6-12
Checking the front brake pads .............................. 6-13
and rear brake shoes
Checking the brake fluid level ............................... 6-14
6 Changing the brake fluid ....................................... 6-15
Checking and lubricating the throttle grip .............. 6-15
and cable
Lubricating the front and rear brakes levers .......... 6-15
Checking and lubricating the centerstand ............. 6-16
Checking the front fork .......................................... 6-16
Checking the steering ........................................... 6-17
Checking the wheel bearings ................................ 6-17
Battery ................................................................... 6-18
Replacing the fuse ................................................ 6-19
Replacing a headlight bulb .................................... 6-20
Replacing the brake taillight bulb .......................... 6-21
Replacing a turn signal light bulb .......................... 6-21
Troubleshooting ..................................................... 6-22
Troubleshooting chart ............................................ 6-23

PERIODIC MAINTENANCE AND MINOR REPAIR
6
•Check tread depth and for damage.
9 * Tires•Replace if necessary.
√√√√ √
•Check air pressure.
•Correct if necessary.
10 * Wheel bearings•Check bearing for looseness or damage.√√√√
11 * Steering bearings•Check bearing play and steering for roughness.√√√√√•Lubricate with lithium-soap-based grease. Every 24,000 km
12 * Chassis fasteners•Make sure that all nuts, bolts and screws are
√√√√ √
properly tightened.
13 Centerstand•Check operation.
√√√√ √
•Lubricate.
14 * Front fork•Check operation and for oil leakage.√√√√
15 * Shock absorber assembly•Check operation and shock absorber for oil leakage.√√√√
16 * Carburetor•Adjust engine idling speed.√√√√√ √
17 * Autolube pump•Check operation.
√√√√
•Bleed if necessary.
18 Final transmission oil•Check vehicle for oil leakage.√√ √•Change.√√√
19 * V-belt•Replace. Every 10,000 km
20 * Front and rear brake
•Check operation.√√√√√ √
switches
ODOMETER READING (x 1,000 km)
NO. ITEMCHECK OR MAINTENANCE JOB
1
ANNUAL
CHECK
6121824
6-3

PERIODIC MAINTENANCE AND MINOR REPAIR
6 If the spark plug shows signs of
electrode erosion and excessive
carbon or other deposits, it should be
replaced.
Specified spark plug:
BR8HS (NGK)
Before installing a spark plug, the spark
plug gap should be measured with a
wire thickness gauge and, if necessary,
adjusted to specification.
Spark plug gap:
0.6 — 0.7 mmClean the surface of the spark plug
gasket and its mating surface, and then
wipe off any grime from the spark plug
threads.
Tightening torque:
Spark plug:
23 Nm (2.3 m
•kg)
NOTE :
If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4 — 1/2 turn
past finger tight. However, the spark
plug should be tightened to the
specified torque as soon as possible.
a
ZAUM0037
a Spark plug gap
EAU04228
Final transmission oil
The final transmission case must be
checked for oil leakage before each
ride. If any leakage is found, have a
Yamaha dealer check and repair the
scooter. In addition, the final transmis-
sion oil must be changed as follows at
the intervals specified in the periodic
maintenance and lubrication chart.
1. Start the engine, warm it up by
riding the scooter for several mi-
nutes, and then stop the engine.
2. Place the scooter on the
centerstand.
3. Place an oil pan under the final
transmission case to collect the
used oil.
6-6

PERIODIC MAINTENANCE AND MINOR REPAIR
64. Remove the oil filler cap and drain
bolt to drain the oil from the final
transmission case.
5. Install the final transmission oil
drain bolt, and then tighten it to
the specified torque.
Tightening torque:
Final transmission oil drain bolt:
17 Nm (1.7 m
•kg)
6. Add the specified amount of the
recommended final transmission
oil, and then install and tighten the
oil filler cap.Recommended final transmission oil:
See page 8-1.
Oil quantity:
0.11 L
EWA00062
•Make sure that no foreign
material enters the final trans-
mission case.
•Make sure that no oil gets on
the tire or wheel.
7. Check the final transmission case
for oil leakage. If oil is leaking,
check for the cause.
1
2
ZAUM0371
1. Oil filler cap
2. Oil drain bolt
EAUM0071
Cleaning the air filter element
The air filter element should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
Clean the air filter element more
frequently if you are riding in unusually
wet or dusty areas.
1. Remove the air filter case cover
by removing the screws.
1
ZAUM0372
1. Screws
6-7

SPECIFICATIONS
8
Model YH50
Dimensions:
Overall length 1.940 mm
Overall width 685 mm
Overall height 1.105 mm
Seat height 765 mm
Wheelbase 1.294 mm
Minimum ground clearance 125 mm
Minimum turning radius 1.800 mm
Weight:
Wet (with oil and a full fuel tank) 78 kg
Engine:
Engine type Air cooled, 2 strokes
Cylinder arrangement Single cylinder, horizontal
Displacement 49.2 cm3
Bore x stroke 40.0 x 39.2
Compression ratio 7.25:1
Starting system type Electric and kick starter
Lubrication system Separate lubrication
(Autolube)
Engine oil:
Type Yamalube 2
or 2 strokes engine oil
Classification Jaso FC ou ISO EG-C, EG-D
Capacity 1.3 LTransmission oil:
Type SAE 10W30 type SE
Capacity
Périodic oil change 0.11L
Total amount 0.13L
Air filter type:Wet type element
Fuel:
Recommended fuel Regular unleaded gasoline
(RON 91 mini)
Fuel tank capacity 7L
Carburetor:
Type / quantity PY-12
Manufacturer GURTNER
Spark plug:
Type / Manufacturer BR8HS / NGK
Spark plug gap 0.6—0.7 mm
Clutch type:Dry, centrifugal automatic
Transmission:
Primary reduction system Helical gear
Primary reduction ratio 52/13 (4.000)
Secondary reduction system Spur gear
Secondary reduction ratio 45/12 (3.750)
Transmission type V-belt automatic
Operation Centrifugal automatic type
8-1
Specifications