2020 YAMAHA PW50 engine

Instrument and control functions
4-6
4
EAU13454
2-stroke en gine oil
Make sure that there is sufficient 2-
stroke engine oil in the oil tank. Add the
recommended 2-stroke engine oil as
necessary.
NOTICE
ECA16671
Make sure that the 2-stroke en gine
oil tank cap is properly installe d.
EAU40702
Fuel cock
The fuel cock supplies fuel from the
tank to the carburetor while filtering it
also.
The fuel cock has two positions:
S (stop)
With the lever in this position, fuel will
not flow. Always return the lever to this
position when the engine is not run-
ning.
O (on)
With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
1. 2-stroke engine oil tank cap
2. Minimum level mark
Recommen ded oil:
See page 9-1.
Oil quantity: 0.30 L (0.32 US qt, 0.26 Imp.qt)
2 1
1. Arrow mark pointing to “S” (stop)
1. Arrow mark pointing to “O” (on)
1
1
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Instrument and control functions
4-7
4
EAU13591
Starter (choke) lever “ ”
Starting a cold engine requires a richer
air-fuel mixture, which is supplied by
the starter (choke).
Move the lever in direction (a) to turn on
the starter (choke).
Move the lever in direction (b) to turn
off the starter (choke).
EAU13681
Kickstarter
To start the engine, fold out the kick-
starter lever, move it down lightly with
your foot until the gears engage, and
then push it down smoothly but force-
fully.
1. Starter (choke) lever “ ”
1
(a)
(b)
1. Kickstarter
1
U2SA86E0.book Page 7 Tuesday, April 30, 2019 11:57 AM

Operation and important ri din g points
6-1
6
EAU15952
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10272
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which coul d cause an acci dent
or injury.
EAU4088B
Startin g an d warmin g up a
col d en gine
1. Turn the fuel cock lever to “O”
(on).
2. Set the engine stop switch to “START”.
3. Turn the starter (choke) on and completely close the throttle. (See
page 4-7.)
4. While applying the front or rear brake, start the engine by pushing
the kickstarter lever down.
5. When the engine is warm, turn the starter (choke) off and set the en-
gine stop switch to “RUN”.
TIP
The engine is warm when it responds
quickly to the throttle with the starter
(choke) turned off.
NOTICE
ECA11043
For maximum en gine life, never ac-
celerate har d when the en gine is
col d!
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Operation and important rid ing points
6-2
6
EAU16661
Startin g a warm en gine
Follow the same procedure as for
starting a cold engine with the excep-
tion that the starter (choke) is not re-
quired when the engine is warm.
Instead, start the engine with the throt-
tle slightly open.
TIP
If the engine does not start after sever-
al kicks, try again with the throttle 1/4
to 1/2 open.
EAU41004
Startin g off
1. While applying the rear brake le-
ver, push the motorcycle off the
centerstand.
2. Completely close the throttle.
3. Set the engine stop switch to “RUN”.
4. Check for oncoming off-road vehi- cles, release the rear brake lever,
and then slowly turn the throttle
grip in order to take off.
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Operation and important rid ing points
6-4
6
EAU42031
En gine break-in
There is never a more important period
in the life of your engine than the first 5
hours of riding. It is also important to
accustom the rider to the motorcycle
during this time. Please read the fol-
lowing information carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
5 hours of operation. The various parts
in the engine wear and polish them-
selves to the correct operating clear-
ances. During this period, prolonged
full-throttle operation or any condition
that might result in engine overheating
must be avoided. However, momen-
tary full-throttle operation under load
(i.e., two to three seconds maximum)
does not harm the engine. Each full-
throttle acceleration should be fol-
lowed with a substantial rest period for
the engine. To allow the engine to cool
down from the temporary buildup of
heat, cruise at a lower engine speed.
After the first 5 hours of operation,
thoroughly check the motorcycle for
loose parts, oil leakage and any other
problems. Be sure to inspect and make
adjustments thoroughly, especially ca-
bles. In addition, check all fittings and
fasteners for looseness, and tighten if
necessary.
NOTICE
ECA10271
If any en gine trou ble shoul d occur
d urin g the en gine break-in perio d,
imme diately have a Yamaha d ealer
check the vehicle.
EAU40723
Parkin g
When parking, stop the engine, and
then turn the fuel cock lever to “S”
(stop).
WARNING
EWA10312
Since the en gine an d exhaust
system can become very hot,
park in a place where ped estri-
ans or chil dren are not likely to
touch them and b e burne d.
 Do not park on a slope or on soft
groun d, otherwise the vehicle
may overturn, increasin g the
risk of a fuel leak an d fire.
 Do not park near g rass or other
flammab le materials which
mi ght catch fire.
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Periodic maintenance an d a djustment
7-2
7
EAU17303
Emission controls not only function to
ensure cleaner air, but are also vital to
proper engine operation and maximum
performance. In the following periodic
maintenance charts, the services relat-
ed to emissions control are grouped
separately. These services require
specialized data, knowledge, and
equipment. Maintenance, replace-
ment, or repair of the emission control
devices and systems may be per-
formed by any repair establishment or
individual that is certified (if applicable).
Yamaha dealers are trained and equipped to perform these particular
services.
EAU17312
Owner’s tool kit
The service information included in this
manual and the tools provided in the
owner’s tool kit are intended to assist
you in the performance of preventive
maintenance and minor repairs. How-
ever, additional tools such as a torque
wrench may be necessary to perform
certain maintenance work correctly.
TIP
If you do not have the tools or experi-
ence required for a particular job, have
a Yamaha dealer perform it for you.
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Periodic maintenance an d a djustment
7-3
7
EAU69180
Perio dic maintenance chart for the emission control system
TIP
Items marked with an asterisk should be performed by a Yamaha dealer as they
require special tools, data and technical skills.
4 *Carburetor Check engine idling speed and
starter operation.
Adjust if necessary.
Clean.
5 *Cylinder head and
exhaust system Check for leakage.
√
Tighten if necessary.
Decarbonize if necessary.
6
*Spark arrester Clean.√
NO. ITEM CHECK OR MAINTENANCE JOB
1 month3 months
6 months
6 months12 months
1
*Fuel line Check fuel hoses for cracks or
damage.√√√ √
√√√ √
√√
√
√
√√
√
√
√√
√ Replace if necessary.
2Spark plug Check condition.
Adjust gap and clean.
Replace if necessary.
3Air filter element
Clean with solvent.
Replace if necessary.
THEREAFTER
EVERYINITIAL
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Periodic maintenance an d a djustment
7-6
7
EAU19607
Checkin g the spark plu g
The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic main-
tenance and lubrication chart. In addi-
tion, the condition of the spark plug
can reveal the condition of the engine.
To remove the spark plu g
1. Remove the spark plug cap.
2. Remove the spark plug as shown, with the spark plug wrench includ-
ed in the owner’s tool kit. To check the spark plu
g
1. Check that the porcelain insulator around the center electrode of the
spark plug is a medium-to-light
tan (the ideal color when the vehi-
cle is ridden normally).
TIP
If the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer check
the vehicle.
2. Check the spark plug for electrodeerosion and excessive carbon or
other deposits, and replace it if
necessary.
3. Measure the spark plug gap with a wire thickness gauge and, if nec-
essary, adjust the gap to specifi-
cation.
1. Spark plug cap
1. Spark plug wrench
1
1
Specified spark plu g:
NGK/BP4HS (South Africa)
NGK/BPR4HS (Canada, Europe,
Oceania)
DENSO/W14FP-L (South Africa)
1. Spark plug gap
Spark plu g g ap:
0.6–0.7 mm (0.024–0.028 in)
1
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