Page 52 of 84
PERIODIC MAINTENANCE AND MINOR REPAIR
6
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.
CAUTION: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.
6-10
EAU00631
Adjusting the carburetor
The carburetor is an important part of
the engine and requires very
sophisticated adjustment. Therefore, all
carburetor adjustments should be left
to a Yamaha dealer, who has the
necessary professional knowledge and
experience.
Page 57 of 84

PERIODIC MAINTENANCE AND MINOR REPAIR
6Observe 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.
EAUM0008*
Changing the brake fluid
Have a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and
lubrication chart. In addition, have the
brake hoses replaced every four years
or whenever there are damaged or
leaking.
6-15
EAU00774
Adjusting the Autolube pump
The Autolube pump is a vital and
sophisticated component of the engine,
which must be adjusted by a Yamaha
dealer at the intervals specified in the
periodic maintenance and lubrication
chart.
Page 75 of 84

SPECIFICATIONS
8
Specifications
Model YQ50
Dimensions:
Overall length 1.743 mm
Overall width 690 mm
Overall height 1.170 mm
Seat height 828 mm
Wheelbase 1.256 mm
Minimum ground clearance 185 mm
Minimum turning radius 1.800 mm
Basic weight:97 kg
(with oil and full fuel tank)
Engine:
Engine type Liquid cooled, 2 stroke
Cylinder arrangement Single cylinder, horizontal
Displacement 49.2 cc
Bore x stroke 40.0 x 39.2
Compression ratio 7.44:1
Starting system Electric and kick starter
Lubrication systemSeparate lubrication (Autolube)
Engine oil:
Type Yamalube 2
or 2 stroke engine oil
Recommended engine oil Jaso FC
classification or ISO EG-C, EG-D
Capacity 1.3 LFinal transmission oil:
Type SAE 10W30 type SE
Quantity 0.13L
Cooling system capacity:1.2L
(total amount)
Air filter type:Wet type element
Fuel:
Recommended fuel Regular unleaded gasoline
(RON 91 mini)
Fuel tank capacity 7L
Carburetor:
Manufacturer DELL'ORTO
Model/quantity PHBN 12HS x1
Spark plug:
Manufacturer/Model NGK / BR8HS
Spark plug gap 0.5—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 43/14 (3.071)
Transmission type V-belt automatic
Operation Centrifugal automatic type
8-1
Page 76 of 84

SPECIFICATIONS
8
Chassis:
Frame type Steel tube underbone
Caster angle 27°
Trail 89.4 mm
Tires:
Front:
Type Tubeless
Size 130/60-13 53L TL
Manufacturer/ Model PIRELLI / SL36
PIRELLI / EVO 21
MICHELIN / BOPPER
Rear:
Type Tubeless
Size 140/60-13 57L TL
anufacturer/ Model PIRELLI / SL36
PIRELLI / EVO 22
MICHELIN / BOPPER
Maximum load* 180 kg
Tir air pressure
(mesured on cold tires):
Up to 90 kg
Front150 kpa
Rear 150 kpa
90kg—maximum*
Front150 kpa
Rear 170 kpa
* Total weight of rider, passenger, cargo and accessoriesWheels:
Front
Type Cast wheel
Size 13 X MT 3.00
Rear
Type Cast wheel
Size 13 X MT 3.50
Brakes:
Front
Type Single disc brake
Operation Right hand operation
Type brake fluid DOT 3 or DOT 4
Rear
Type Single disc brake
Operation Left hand operation
Type brake fluid DOT 3 or DOT 4
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 or Coil spring/Gas-oil damper
(Depends on model)
Wheel travel:
Front wheel travel 80 mm
Rear wheel travel 72 mm
8-2
Page 77 of 84
SPECIFICATIONS
8
Electrical:
Ignition system type C.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, 2Wx1
Turn signal indicator light 12V, 2Wx1
Oil warning light 12V, 2Wx1
Temperature indicator light 12V, 1,2Wx1
Fuses:
Main fuse 7.5 A
8-3