Page 15 of 84
2
DESCRIPTION
Left view
1. Rear brake lever (page 3-5, 6-13, 6-16)
2. Left handlebar switches (page 3-4)
3. Speedometer (page 3-3)
4. Main switch/steering lock (page 3-1, 3-9)
2-1
1
23
4
68
7
5
5. Final transmission oil filler cap (page 6-7)
6. Centerstand (page 6-16)
7. Kick starter (page 3-7)
8. Air filter (page 6-9)
Page 42 of 84

EAU00462
PERIODIC MAINTENANCE AND MINOR REPAIR
Periodic maintenance and lubrication chart ............ 6-2
Removing and installing cowling and panel ............ 6-5
Cowling A ................................................................ 6-5
Panel A .................................................................... 6-5
Checking the spark plug ......................................... 6-6
Final transmission oil .............................................. 6-7
Coolant .................................................................... 6-8
Cleaning the air filter element ................................. 6-9
Adjusting the carburetor ........................................ 6-10
Adjusting the throttle cable free play ..................... 6-11
Tires ...................................................................... 6-11
Wheels .................................................................. 6-13
Adjusting the front and rear brake lever
free play ................................................................ 6-13
Checking the front and rear brake pads ................ 6-14
Checking the brake fluid level ............................... 6-14
6 Changing the brake fluid ....................................... 6-15
Adjusting the autolube pump ................................ 6-15
Checking and lubricating the cables ..................... 6-16
Lubricating the front and rear brakes levers .......... 6-16
Checking and lubricating the centerstand ............. 6-16
Checking the front fork .......................................... 6-17
Checking the steering ........................................... 6-17
Checking the wheel bearings ................................ 6-18
Battery ................................................................... 6-18
Replacing the fuse ................................................ 6-20
Replacing a headlight bulb .................................... 6-20
Replacing tail/brake light bulb ............................... 6-21
Replacing a turn signal light bulb .......................... 6-22
Troubleshooting ..................................................... 6-22
Troubleshooting chart ............................................ 6-23
Engine overheating ............................................... 6-24
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 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