Page 40 of 80

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
Page 43 of 80

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
Page 68 of 80

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