engine YAMAHA SR400 2016 User Guide

Instrument and control functions
3-9
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU13222
Fuel
Make sure there is sufficient gasoline in
the tank.
WARNING
EWA10882
Gasoline and gasoline vapors are
extremely flammable. To avoid fires
and explosions and to reduce the
risk of injury when refueling, follow
these instructions. 1. Before refueling, turn off the en- gine and be sure that no one is sit-
ting on the vehicle. Never refuel
while smoking, or while in the vicin-
ity of sparks, open flames, or other
sources of ignition such as the pilot
lights of water heaters and clothes
dryers.
2. Do not overfill the fuel tank. When refueling, be sure to insert the
pump nozzle into the fuel tank filler
hole. Stop filling when the fuel
reaches the bottom of the filler
tube. Because fuel expands when
it heats up, heat from the engine or
the sun can cause fuel to spill out
of the fuel tank.
3. Wipe up any spilled fuel immedi- ately. NOTICE: Immediately wipe off spilled fuel with a clean, dry,
soft cloth, since fuel may deteri-
orate painted surfaces or plastic
parts.
[ECA10072]
4. Be sure to securely close the fuel
tank cap.
WARNING
EWA15152
Gasoline is poisonous and can
cause injury or death. Handle gaso-
line with care. Never siphon gaso-
line by mouth. If you should swallow
some gasoline or inhale a lot of gas-
oline vapor, or get some gasoline in
your eyes, see your doctor immedi-
ately. If gasoline spills on your skin,
wash with soap and water. If gaso-
line spills on your clothing, change
your clothes.
EAU57691
NOTICE
ECA11401
Use only unleaded gasoline. The use
of leaded gasoline will cause severe
damage to internal engine parts,
such as the valves and piston rings,
as well as to the exhaust system.
Your Yamaha engine has been de-
signed to use regular unleaded gaso-
line with a research octane number of
95 or higher. If knocking (or pinging) oc-
1. Maximum fuel level
2. Fuel tank filler tube
1 2
Recommended fuel:
Regular unleaded gasoline (Gasohol
[E10] acceptable)
Fuel tank capacity:
12 L (3.2 US gal, 2.6 Imp.gal)
Fuel reserve amount (when the fuel
level warning light comes on): 2.2 L (0.58 US gal, 0.48 Imp.gal)
2RD-28199-E1.book 9 ページ ２０１５年９月３日　木曜日　午後３時４２分

Instrument and control functions
3-11
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU13434
Catalytic converter
This model is equipped with a catalytic
converter in the exhaust system.
WARNING
EWA10863
The exhaust system is hot after op-
eration. To prevent a fire hazard or
burns:
Do not park the vehicle near
possible fire hazards such as
grass or other materials that
easily burn.
Park the vehicle in a place
where pedestrians or children
are not likely to touch the hot
exhaust system.
Make sure that the exhaust sys-
tem has cooled down before do-
ing any maintenance work.
Do not allow the engine to idle
more than a few minutes. Long
idling can cause a build-up of
heat.
NOTICE
ECA10702
Use only unleaded gasoline. The use
of leaded gasoline will cause unre-
pairable damage to the catalytic
converter.
EAU59491
Fuel cock
The fuel cock regulates and filters the
fuel supply from the fuel tank.
The fuel cock has two positions:
ON
With the lever in this position, fuel will
be supplied to the engine. Normal oper-
ation is done with the lever in this posi-
tion.
OFF
With the lever in this position, fuel will
not flow. Use this lever position when
performing certain maintenance work
or when storing the vehicle for a pro-
longed time.
1. Arrow mark positioned over “ON”
1. Arrow mark positioned over “OFF”
1
1
2RD-28199-E1.book 11 ページ ２０１５年９月３日　木曜日　午後３時４２分

Instrument and control functions
3-12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU13651
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. This model is equipped with a pri-
mary kickstarter, allowing the engine to
be started in any gear if the clutch is
disengaged. However, shifting the
transmission into the neutral position
before starting is recommended.
EAU13701
Decompression lever
When this lever is pulled, the exhaust
valve is forced open so that the com-
pression pressure can be reduced.
This allows the piston to be moved just
past the compression stroke before
kick starting. (See page 5-2.)
1. Kickstarter
1
1. Decompression lever
1
2RD-28199-E1.book 12 ページ ２０１５年９月３日　木曜日　午後３時４２分

Instrument and control functions
3-15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU66820
Ignition circuit cut-off system
The ignition circuit cut-off system (com-
prising the sidestand switch, clutch
switch and neutral switch) has the fol-
lowing functions.
It prevents starting when the trans-
mission is in gear and the sides-
tand is up, but the clutch lever is
not pulled.
It prevents starting when the trans-
mission is in gear and the clutch le-
ver is pulled, but the sidestand is
still down.
It cuts the running engine when the
transmission is in gear and the sid-
estand is moved down.
Periodically check the operation of the
ignition circuit cut-of f system according
to the following procedure.
2RD-28199-E1.book 15 ページ ２０１５年９月３日　木曜日　午後３時４２分

Instrument and control functions
3-16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
With the engine turned off:
1. Move the sidestand down.
2.
Make sure that the engine stop switch
is set to “ ”.
3. Turn the key on.
4. Shift the transmission into the neutral position.
5. Push the kick starter lever down.
Does the engine start?
With the engine still running:
6. Move the sidestand up.
7. Keep the clutch lever pulled.
8. Shift the transmission into gear.
9. Move the sidestand down.
Does the engine stall?
After the engine has stalled:
10. Move the sidestand up.
11. Keep the clutch lever pulled.
12. Push the kick starter lever down.
Does the engine start?
The system is OK. The motorcycle can
be ridden.
The neutral switch may not be working
correctly.
The motorcycle should not be ridden
until checked by a Yamaha dealer.
The sidestand switch may not be
working correctly.
The motorcycle should not be ridden
until checked by a Yamaha dealer.
The clutch switch may not be working
correctly.
The motorcycle should not be ridden
until checked by a Yamaha dealer.
WARNING
The vehicle must be placed on the centerstand during this inspection.
If a malfunction is noted, have a Yamaha dealer check the system
before riding.
YES NO
YESNO
YESNO
2RD-28199-E1.book 16 ページ ２０１５年９月３日　木曜日　午後３時４２分

4-1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
For your safety – pre-operation checks
EAU63440
Inspect your vehicle each time you use it to make sure the vehicle is in safe oper-
ating condition. Always follow the in spection and maintenance procedures and
schedules described in the Owner’s Manual.
WARNING
EWA11152
Failure to inspect or maintain the vehicle properly increases the possibility
of an accident or equipment damage. Do not operate the vehicle if you find
any problem. If a problem cannot be corrected by the procedures provided
in this manual, have the vehicle inspected by a Yamaha dealer.
Before using this vehicle, check the following points:
ITEM CHECKSPAGE
Fuel Check fuel level in fuel tank.
Refuel if necessary.
Check fuel line for leakage.
Check fuel tank breather hose
for obstructions, cracks or
damage, and check hose connection. 3-9, 3-10
Engine oil Check oil level in oil tank.
If necessary, add recommended oil to specified level.
Check vehicle for oil leakage. 6-9
Front brake Check operation.
If soft or spongy, have Yamaha dealer bleed hydraulic
system.
Check lever free play.
Adjust if necessary.
Check brake pads for wear.
Replace if necessary.
Check fluid level in reservoir.
If necessary, add specified brak e fluid to specified level.
Check hydraulic system for leakage. 6-19,
6-22, 6-23
Rear brake Check operation.
Check pedal free play.
Adjust if necessary. 6-20,
6-22
Clutch Check operation.
Lubricate cable if necessary.
Check lever free play.
Adjust if necessary. 6-18
Throttle grip Make sure that operation is smooth.
Check throttle grip free play.
If necessary, have Yamaha dealer adjust throttle grip
free play and lubricate cable and grip housing. 6-14,
6-27
Control cables Make sure that operation is smooth.
Lubricate if necessary. 6-27
2RD-28199-E1.book 1 ページ ２０１５年９月３日　木曜日　午後３時４２分

5-1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Operation and important riding points
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 could cause an accident
or injury.
EAU59360
TIP
This model is equipped with:
a lean angle sensor to stop the en-
gine in case of a turnover. In this
case, turn the key to “OFF” and
then to “ON”. Failing to do so will
prevent the engine from starting
even though the engine will crank
when pushing the kick starter lever
down.
an engine auto-stop system. The
engine stops automatically if left
idling for 20 minutes. If the engine
stops, simply push the kick starter
lever down to restart the engine.
2RD-28199-E1.book 1 ページ ２０１５年９月３日　木曜日　午後３時４２分

Operation and important riding points
5-2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU59532
Starting the engine
In order for the ignition circuit cut-off
system (page 3-15) to enable starting,
one of the following conditions must be
met:
The transmission is in the neutral
position.
The transmission is in gear with
the clutch lever pulled and the sid-
estand up.
1. Turn the fuel cock lever to “ON”.
2. Turn the key to “ON” and set the engine stop switch to “ ”.
The engine trouble warning light
and fuel level warning light should
come on for a few seconds, then
go off.
NOTICE
ECA23270
If a warning light does not come on
initially when the key is turned to
“ON”, or if a warning light remains
on, see page 3-2 for the correspond-
ing warning light circuit check.
3. Shift the transmission into the neu- tral position. The neutral indicator
light should come on. If not, ask a
Yamaha dealer to check the elec-
trical circuit.
4. Completely close the throttle and apply the decompression lever.
5. Slowly push the kickstarter lever down until the starting mark shows
on the kick indicator. 6. Release the decompression lever,
release the kickstarter lever, and
then push the kickstarter lever
down forcefully to start the engine.
NOTICE
ECA11043
For maximum engine life, never ac-
celerate hard when the engine is
cold!
1. Starting mark
2. Kick indicator
21
2RD-28199-E1.book 2 ページ ２０１５年９月３日　木曜日　午後３時４２分

Operation and important riding points
5-3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
EAU59470
Starting trouble
If the engine fails to start after 4 to 5
kicks, clear out the combustion cham-
ber with the following procedure. 1. Turn the key to “OFF”.
2. While applying the decompression lever, fully open the throttle grip
and push the kickstarter lever
down 4 to 5 times.
3. Turn the key to “ON” and retry starting the engine.
EAU16673
Shifting
Shifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.
TIP
To shift the transmission into the neu-
tral position, press the shift pedal down
repeatedly until it reaches the end of its
travel, and then slightly raise it.
NOTICE
ECA10261
Even with the transmission in
the neutral position, do not
coast for long periods of time
with the engine off, and do not
tow the motorcycle for long dis-
tances. The transmission is
properly lubricated only when
the engine is running. Inade-
quate lubrication may damage
the transmission.
Always use the clutch while
changing gears to avoid damag-
ing the engine, transmission,
and drive train, which are not
designed to withstand the
1. Shift pedal
2. Neutral position
1
2
1 3 4 5
N
2
2RD-28199-E1.book 3 ページ ２０１５年９月３日　木曜日　午後３時４２分

Operation and important riding points
5-4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
shock of forced shifting.
EAU16682To start out and accelerate 1. Pull the clutch lever to disengage the clutch.
2. Shift the transmission into first gear. The neutral indicator light
should go out.
3. Open the throttle gradually, and at the same time, release the clutch
lever slowly.
4. At the recommended shift points shown in the following table, close
the throttle, and at the same time,
quickly pull the clutch lever in.
5. Shift the transmission into second gear. (Make sure not to shift the
transmission into the neutral posi-
tion.)
6. Open the throttle part way and gradually release the clutch lever.
7. Follow the same procedure when shifting to the next higher gear.
TIP
When shifting gears in normal operat-
ing conditions, use the recommended
shift points.
EAU16701To decelerate1. Apply both the front and the rear brakes to slow the motorcycle.
2. Shift the transmission into first gear when the motorcycle reaches
20 km/h (12 mph). If the engine is
about to stall or runs very roughly,
pull the clutch lever in and use the
brakes to stop the motorcycle.
3. Shift the transmission into the neu- tral position when the motorcycle
is almost completely stopped. The neutral indicator light should come
on.
EAU64120Recommended shift points
The recommended shift points during
acceleration and deceleration are
shown in the table below.
Shift up points:
1st  2nd: 20 km/h (12 mph)
2nd  3rd: 30 km/h (19 mph)
3rd  4th: 40 km/h (25 mph)
4th  5th: 50 km/h (31 mph)
Shift down points: 5th  4th: 35 km/h (22 mph)
4th  3rd: 25 km/h (16 mph)
3rd  2nd: 20 km/h (12 mph)
2nd  1st: 20 km/h (12 mph)
2RD-28199-E1.book 4 ページ ２０１５年９月３日　木曜日　午後３時４２分