Page 45 of 80

PERIODIC MAINTENANCE AND MINOR REPAIR
6 2. Pull the air filter element out, clean
it with solvent, and then squeeze
the remaining solvent out.EW000075
Use only a dedicated parts cleaning
solvent. To avoid the risk of fire or
explosion, do not use gasoline or
solvents with a low flash point.
EC000089
To avoid damaging the foam material,
handle it gently and carefully, and do
not twist or wring it.
1
ZAUM0373
1
4 32
ZAUM0156
3. Apply oil of the recommended
type to the entire surface of the
element, and then squeeze the
excess oil out.
NOTE :
The air filter element should be wet but
not dripping
Recommended oil:
Engine oil
4. Insert the element into the air filter
case.
1. Air filter element
EC000082
•Make sure that the air filter
element is properly seated in
the air filter case.
•The engine should never be
operated without the air filter
element installed, otherwise the
piston(s) and/or cylinder(s)
may become excessively worn.
5. Install the air filter case cover by
installing the screws.
6-8
Page 51 of 80

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU00732
Checking the brake fluid
level
Insufficient brake fluid may allow air to
enter the brake system, possibly
causing it to become ineffective.
Before riding, check that the brake fluid
is above the minimum level mark and
replenish if necessary. A low brake fluid
level may indicate worn brake pads
and/or brake system leakage. If the
brake level is low, be sure to check the
brake pads for wear and the brake
system for leakage.Observe these precautions:
•When checking the fluid level,
make sure that the top of the
master cylinder is level by turning
the handlebars.
•Use only the recommended
quality brake fluid, otherwise the
rubber seals may deteriorate,
causing leakage and poor braking
performance.
Recommended brake fluid:
DOT 4
NOTE :
If DOT 4 is not available, DOT 3 can be
used.
•Refill with the same type of brake
fluid. Mixing fluids may result in a
harmful chemical reaction and
lead to poor braking performance.
•Be careful that water does not
enter the master cylinder when
refilling. Water will significantly
lower the boiling point of the fluid
and may result in vapor lock.
•Brake fluid may deteriorate
painted surfaces or plastic parts.
Always clean up spilled fluid
immediately.
•As the brake pads wear, it is nor-
mal for the brake fluid level to
gradually go down. However, if the
brake fluid level goes down
suddenly, have a Yamaha dealer
check the cause.
1
ZAUM0377
1. Brake fluid level
6-14
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
Page 69 of 80
SPECIFICATIONS
8
Chassis:
Frame type Steel tube underbone
Caster angle ((degree)) 25°
Trail 101.3 mm
Tires:
Front:
Type Tubeless
Size 2 1/2-16 42M
Manufacturer / Model MICHELIN / M29S TT
Rear:
Type Tubeless
Size 2 3/4-16 46M
Manufacturer / Model MICHELIN / M29S TT
Maximum load * 182 Kg
Air pressure (cold tire):
Up to 90 Kg load*
Front180 kpa
Rear 190 kpa
90 kg load — maximum
load *
Front180 kpa
Rear 210 kpa
* Total weight of rider, passenger, cargo and accessories.Wheels:
Front
Type Cast wheel
Size 16 X MT 1.60
Rear
Type Cast wheel
Size 16 X MT 1.85
Brakes:
Front
Type Single disc brake
Operation Right hand operation
Type brake fluid DOT 4
Rear
Type Single drum brake
Operation Left hand operation
Suspension:
Front suspension Telescopic fork
Rear suspension Unit swing
Shock absorber:
Front fork type Coil spring/oil damper
Rear shock absorber Coil spring/oil damper
assembly type
Wheel travel:
Front wheel travel 80 mm
Rear wheel travel 70 mm
8-2
Page 70 of 80
SPECIFICATIONS
8
Electrical:
Ignition system typeC.D.I
Charging system Flywheel magneto
Battery
Model GM4-3B, YB4L-B, FB4L-B
Voltage/capacity 12 V / 4 Ah
Headlight type:Bulb
Bulbs (voltage/wattage x quantity):
Headlight 12V, 35W/35Wx1
Brake/brake light 12V, 5W/21Wx1
Turn signal light
Front 12V, 10Wx2
Rear 12V, 10Wx2
Meter lights 12V, 1.2Wx2
High beam indicator light 12V, 1.2Wx1
Turn signal indicator light 12V, 1.2Wx1
Oil warning light 12V, 2Wx1
Fuses:
Main fuse 7.5 A
8-3