Page 15 of 72
EAU32230
CS50Z
DESCRIPTION
2-4
2
1. Grab bar (page 5-2)
2. Oil tank cap (page 3-7/page 3-9)
3. Fuel tank cap (page 3-7)
4. Seat (page 3-10)
5. Battery (page 6-19)
6. Fuse (page 6-20)7. Luggage hook (page 3-12)
8. Coolant reservoir cap (page 6-8)
9. Centerstand (page 6-17)
10. Passenger footrest
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Page 30 of 72

PRE-OPERATION CHECKS
4-2
4
EAU15605
Pre-operation check list
ITEM CHECKS PAGE
• Check fuel level in fuel tank.
Fuel• Refuel if necessary.3-8
• Check fuel line for leakage.
• Check oil level in oil tank.
2-stroke engine oil• If necessary, add recommended oil to specified level. 3-9
• Check vehicle for oil leakage.
Final transmission oil• Check vehicle for oil leakage. 6-7
• Check coolant level in reservoir.
Coolant (for CS50Z)• 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.
• Check brake pads for wear.
Front brake• Replace if necessary. 6-13, 6-14, 6-15
• Check fluid level in reservoir.
• If necessary, add recommended brake fluid to specified level.
• Check hydraulic system for leakage.
• Check operation.
Rear brake• Lubricate cable if necessary.
6-13, 6-14
• Check lever free play.
• Adjust if necessary.
• Make sure that operation is smooth.
Throttle grip• Check cable free play.
6-10, 6-16
• If necessary, have Yamaha dealer adjust cable free play and lubricate
cable and grip housing.
• Check for damage.
Wheels and tires• Check tire condition and tread depth.
6-11, 6-12
• Check air pressure.
• Correct if necessary.
Brake levers• Make sure that operation is smooth.
• Lubricate lever pivoting points if necessary.6-16
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Page 43 of 72

EWA11310
s s
WARNING
●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.
EAUS1200
Coolant (only for liquid-
cooled models)
The coolant level should be checked
before each ride. In addition, the coo-
lant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUM2101
To check the coolant level
1. Place the vehicle on a level surfa-
ce and hold it in an upright posi-
tion.
NOTE:
●The coolant level must be chec-
ked on a cold engine since the
level varies with engine tempera-
ture.
●Make sure that the vehicle is
positioned straight up when
checking the coolant level. A
slight tilt to the side can result in
a false reading.
2. Check the coolant level through
the check window.
NOTE:
The coolant should be between the
minimum and maximum level marks.
1. Coolant level window
2. Maximum level mark
3. Minimum level mark
3. If the coolant is at or below the
minimum level mark, remove the
cowling A. (See page 6-5.)
4. Open the reservoir cap, and then
add coolant to the maximum
level mark.
Coolant reservoir capacity:
0.25 L (0.26 US qt) (0.22 Imp.qt)
Recommended final transmission
oil:
See page 8-1.
Oil quantity:
0.11 L (0.12 US qt) (0.10 Imp.qt)
PERIODIC MAINTENANCE AND MINOR REPAIR
6-8
6
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Page 44 of 72

1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
ECA10471
CAUTION:
●If coolant is not available, use
distilled water or soft tap water
instead. Do not use hard water
or salt water since it is harmful
to the engine.
●If water has been used instead
of coolant, replace it with coo-
lant as soon as possible, other-
wise the cooling system will
not be protected against frost
and corrosion.
●If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content ofthe coolant as soon as possi-
ble, otherwise the effective-
ness of the coolant will be
reduced.
EWA10380
s s
WARNING
Never attempt to remove the radia-
tor cap when the engine is hot.
5. Close the reservoir cap, and then
install the cowling.
EAU33030
Changing the coolantEWA10380
s s
WARNING
Never attempt to remove the radia-
tor cap when the engine is hot.
The coolant must be changed at the
intervals specified in the periodic
maintenance and lubrication chart.
Have a Yamaha dealer change the
coolant.
EAU40370
Air filter element
The air filter element must be cleaned
and replaced at the intervals specified
in the periodic maintenance and lubri-
cation chart. Have a Yamaha dealer
clean and replace the air filter ele-
ment.
PERIODIC MAINTENANCE AND MINOR REPAIR
6-9
6
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Page 61 of 72

Engine overheating (for CS50Z)EWA10400
s s
WARNING
●Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
●After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the his-
sing sound has stopped, press down on the cap while turning it counterclockwise, and then remove the cap.
PERIODIC MAINTENANCE AND MINOR REPAIR
6-26
6
Wait until the
engine has cooled.Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.
The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.
Add coolant. (See NOTE.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
NOTE:
If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended
coolant as soon as possible.
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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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