Page 10 of 72

Gasoline and exhaust gas
●GASOLINE IS HIGHLY FLAMMA-
BLE:
• Always turn the engine off
when refueling.
• Take care not to spill any gaso-
line on the engine or exhaust
system when refueling.
• Never refuel while smoking or
in the vicinity of an open flame.
●Never start the engine or let it run
for any length of time in a closed
area. The exhaust fumes are poi-
sonous and may cause loss of
consciousness and death within
a short time. Always operate your
scooter in an area that has ade-
quate ventilation.
●Always turn the engine off before
leaving the scooter unattended
and remove the key from the
main switch. When parking the
scooter, note the following:
• The engine and exhaust sys-
tem may be hot, therefore,
park the scooter in a place
where pedestrians or children
are not likely to touch these hot
areas.• Do not park the scooter on a
slope or soft ground, otherwise
it may fall over.
• Do not park the scooter near a
flammable source (e.g., a kero-
sene heater, or near an open
flame), otherwise it could catch
fire.
●If you should swallow any gasoli-
ne, inhale a lot of gasoline vapor,
or allow gasoline to get into your
eyes, see your doctor immedia-
tely. If any gasoline spills on your
skin or clothing, immediately
wash the affected area with soap
and water and change your clot-
hes.
EAU10371
Further safe-riding points
●Be sure to signal clearly when
making turns.
●Braking can be extremely difficult
on a wet road. Avoid hard bra-
king, because the scooter could
slide. Apply the brakes slowly
when stopping on a wet surface.
●Slow down as you approach a
corner or turn. Once you have
completed a turn, accelerate
slowly.
●Be careful when passing parked
cars. A driver might not see you
and open a door in your path.
●Railroad crossings, streetcar
rails, iron plates on road cons-
truction sites, and manhole
covers become extremely slip-
pery when wet. Slow down and
cross them with caution. Keep
the scooter upright, otherwise it
could slide out from under you.
●The brake pads could get wet
when you wash the scooter. After
washing the scooter, check the
brakes before riding.
1
tSAFETY INFORMATION
1-4
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Page 32 of 72

EAU15980
EWA10870
s s
WARNING
●Become thoroughly familiar
with all operating controls and
their functions before riding.
Consult a Yamaha dealer
regarding any control or func-
tion that you do not thoroughly
understand.
●Never start the engine or ope-
rate it in a closed area for any
length of time. Exhaust fumes
are poisonous, and inhaling
them can cause loss of cons-
ciousness and death within a
short time. Always make sure
that there is adequate ventila-
tion.
●For safety, always start the
engine with the centerstand
down.
EAU16561
Starting a cold engineECA10250
CAUTION:
See page 5-4 for engine break-in
instructions prior to operating the
vehicle for the first time.
1. Turn the key to “h”, and when
the oil level warning light comes
on, turn it to “f”.
ECA10240
CAUTION:
If the oil level warning light does
not come on, have a Yamaha dealer
check the electrical circuit.
2. Close the throttle completely.
3. While applying the front or rear
brake, start the engine by pus-hing the start switch or by pus-
hing the kickstarter lever down.
NOTE:
If the engine fails to start by pushing
the start switch, release the switch,
wait a few seconds, and then try
again. Each starting attempt should
be as short as possible to preserve
the battery. Do not crank the engine
more than 5 seconds on any one
attempt. If the engine does not start
with the starter motor, try using the
kickstarter.
ECA11040
CAUTION:
For maximum engine life, never
accelerate hard when the engine is
cold!
ZAUM0367
m
OPERATION AND IMPORTANT RIDING POINTS
5-1
5
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Page 34 of 72

EAU16792
Braking
1. Close the throttle completely.
2. Apply both front and rear brakes
simultaneously while gradually
increasing the pressure.
EWA10300
s s
WARNING
●Avoid braking hard or suddenly
(especially when leaning over
to one side), otherwise the sco-
oter may skid or overturn.
●Railroad crossings, streetcar
rails, iron plates on road cons-
truction sites, and manhole
covers become extremely slip-
pery when wet. Therefore, slow
down when approaching suchareas and cross them with cau-
tion.
●Keep in mind that braking on a
wet road is much more difficult.
●Ride slowly down a hill, as bra-
king downhill can be very diffi-
cult.
EAU16820
Tips for reducing fuel
consumption
Fuel consumption depends largely on
your riding style. Consider the follo-
wing tips to reduce fuel consumption:
●Avoid high engine speeds during
acceleration.
●Avoid high engine speeds with no
load on the engine.
●Turn the engine off instead of let-
ting it idle for an extended length
of time (e.g., in traffic jams, at
traffic lights or at railroad cros-
sings).
OPERATION AND IMPORTANT RIDING POINTS
5-3
5
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Page 66 of 72

Dimensions:Overall length:
1740 mm (68.5 in)
Overall width:
675 mm (26.6 in)
Overall height:
1065 mm (41.9 in)
Seat height:
770 mm (30.3 in)
Wheelbase:
1210 mm (47.6 in)
Ground clearance:
132 mm (5.19 in)
Weight:With oil and fuel:
CS50/CS50M: 81.0 kg (178.6 lb)
CS50Z: 84.0 kg (185.2 lb)
Engine:Engine type:
CS50/CS50M: Air cooled 2-stroke
CS50Z: Liquid cooled 2-stroke
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
49.0 cm
3(2.99 cu.in)
Bore x stroke:
40.0 x 39.2 mm (1.57 x 1.54 in)
Compression ratio:
CS50: 11.60:1
CS50M: 10,10 :1
CS50Z: 11.40 :1
Starting system:
Electric starter and kickstarterLubrication system:
Separate lubrication (Yamaha autolube)
Engine oil:Type:
YAMALUBE 2-cycle oil or 2-stroke engine
oil (JASO FC grade) or (ISO EG-C or EG-
D grade)
Engine oil quantity:
Quantity:
1.4 L (1.48 US qt) (1.23 Imp.qt)
Final transmission oil:Type:
SAE10W30 type SE motor oil
Quantity:
0.11 L (0.12 US qt) (0.10 Imp.qt)
CS50Z: Cooling system:Coolant reservoir capacity (up to the maxi-
mum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
Radiator capacity (including all routes):
0.91 L (0.96 US qt) (0.80 Imp.qt)
Air filter:Air filter element:
Wet element
Fuel:Recommended fuel:
Regular unleaded gasoline only
Fuel tank capacity:
5.5 L (1.45 US gal) (1.21 Imp.gal)
Fuel reserve amount
1.9 L (0.50 US gal) (0.42 Imp.gal)
Carburetor:Manufacturer:
GURTNERType x quantity:
PY 12 x 1
Spark plug(s):Manufacturer/model:
CS50-CS50Z: NGK/BR8HS
CS50M: NGK/BPR4HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Clutch:Clutch type:
Dry, centrifugal automatic
Final transmission oil:Primary reduction system:
Helical gear
Primary reduction ratio:
52 x 13 (4.000)
Secondary reduction system:
Spur gear
Secondary reduction ratio:
CS50: 42 x 13 (3.231)
CS50M: 45 x 12(3.750)
CS50Z: 43 x 13 (3.308)
Transmission type:
V-belt automatic
Operation:
Centrifugal automatic type
Chassis:Frame type:
Steel tube underbone
Caster angle:
25.00 °
Trail:
80.0 mm (3.15 in)
SPECIFICATIONS
8-1
8
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