
INSTRUMENT AND CONTROL FUNCTIONS
3ZAUM0204
1
2
ZAUM0263
1. Storage compartment B
2. Oil tank cap
3-8
EAU03750
2-stroke engine oil
Make sure that there is sufficient oil in
the  2-stroke  engine  oil  tank.  Add  the
recommended  2-stroke  engine  oil  if
necessary.
NOTE :
Make sure that the 2-stroke engine oil
tank cap is properly installed.
Recommended oil:
Yamalube 2
or equivalent 2-stroke engine oil
(JASO grade "FC", or ISO
grades "EG-C" or "EG-D")
Oil quantity:
1.3 L
EAUM0082
2-stroke engine oil tank cap
The  2-stroke  engine  oil  tank  cap  is
located  in  the  storage  compartment.
(See  page  3-11  for  storage
compartment  opening  and  closing
procedures.)
1. To remove the 2-stroke engine oil
tank cap, pull it off.2. To  install  the  2-stroke  engine  oil
tank cap, push it into the oil tank
opening.
NOTE :
Make sure that the 2-stroke engine oil
tank  cap  is  properly  installed  before
riding the scooter. 

PRE-OPERATION CHECKS
4
EAU03439
Pre-operation check list
ITEM CHECKS PAGE
• 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.
Two-stroke engine oil• If necessary, add recommended oil to specified level. 3-8, 6-15
• Check vehicle for oil leakage.
Final transmission oil• Check vehicle for oil leakage. 6-7
• Check coolant level in reservoir.
Coolant• If necessary, add recommended coolant to specified level. 6-8
• Check cooling system for leakage.
• 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.
• If soft or spongy, have Yamaha dealer bleed hydraulic system.
Rear 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.
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.
4-1 

PERIODIC MAINTENANCE AND MINOR REPAIR
6
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.
WARNING
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.
4. 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:
18 Nm (1.8 m
•kgf)
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:
0.13 L
12ZAUM0273
1. Final transmission oil drain bolt
2. Oil filler cap
6-7 

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. 

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. 

PERIODIC MAINTENANCE AND MINOR REPAIR
6
ZAUM0061
EAU03118
Lubricating the front and rear
brake levers
The pivoting points of the front and rear
brake levers must be lubricated at the
intervals specified in the periodic main-
tenance and lubrication chart.
Recommended lubricant:
Lithium-soap-based  grease
(all-purpose grease)
ZAUM0062
EAU04123
Checking and lubricating the
centerstand
The operation of the centerstand should
be checked before each ride, and the
pivots and metal-to-metal contact sur-
faces should be lubricated if necessary.
EWA00055
If the centerstand does not move up
and down smoothly, have a Yamaha
dealer check or repair it.
Recommended lubricant:
Lithium-soap-based  grease
(all-purpose grease)
WARNING
6-16
EAU02962
Checking and lubricating the
cables
The  operation  of  all  control  cables  and
the  condition  of  the  cables  should  be
checked before each ride, and the cables
and  cable  ends  should  be  lubricated  if
necessary.  If a cable is damaged or does
not move smoothly, have a Yamaha dea-
ler check or replace it.
Recommended lubricant:
Engine oil
EW000112
Damage  to  the  outer  sheath  may
interfere with proper cable operation
and will cause the inner cable to rust.
Replace  a  damaged  cable  as  soon
as  possible  to  prevent  unsafe  con-
ditions.
WARNING 

SCOOTER CARE AND STORAGE
7After cleaning
1. Dry the scooter with a chamois or
an absorbing cloth.
2. Use  a  chrome  polish  to  shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system.  (Even  the  thermally
induced  discoloring  of  stainless-
steel  exhaust  systems  can  be
removed through polishing.)
3. To  prevent  corrosion,  it  is
recommended  to  apply  a  corro-
sion protection spray on all metal,
including  chrome-  and  nickel-
plated, surfaces.
4. Use  spray  oil  as  a  universal
cleaner to remove any remaining
dirt.
5. Touch  up  minor  paint  damage
caused by stones, etc.
6. Wax all painted surfaces.
7. Let  the  scooter  dry  completely
before storing or covering it.
EWA00002
•Make sure that there is no oil or
wax  on  the  brakes  or  tires.  If
necessary, clean the brake discs
and brake linings with a regular
brake  disc  cleaner  or  acetone,
and  wash  the  tires  with  warm
water and a mild detergent.
•Before  operating  the  scooter
test its braking performance and
cornering behavior.
ECA00013
•Apply spray oil and wax sparingly
and  make  sure  to  wipe  off  any
excess.
•Never  apply  oil  or  wax  to  any
rubber and plastic parts, but treat
them with a suitable care product.
•Avoid  using  abrasive  polishing
compounds  as  they  will  wear
away the paint.
NOTE :
Consult a Yamaha dealer for advice on
what products to use.
Storage
Short-term
Always store your scooter in a cool, dry
place  and,  if  necessary,  protect  it
against dust with a porous cover.
ECA00015
•Storing the scooter in a poorly
ventilated  room  or  covering  it
with a tarp, while it is still wet,
will allow water and humidity to
seep in and cause rust.
•To  prevent  corrosion,  avoid
damp cellars, stables (because
of  the  presence  of  ammonia)
and  areas  where  strong
chemicals are stored.
WARNING
CAUTION:
CAUTION:
7-3 

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