engine YAMAHA SR400 2016 Owner's Manual

Operation and important riding points
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EAU16811
Tips for reducing fuel
consumption
Fuel consumption depends largely on
your riding style. Consider the following
tips to reduce fuel consumption:
Shift up swiftly, and avoid high en-
gine speeds during acceleration.
Do not rev the engine while shifting
down, and 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 crossings).
EAU16842
Engine break-in
There is never a more important period
in the life of your engine than the period
between 0 and 1600 km (1000 mi). For
this reason, you should read the follow-
ing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1600 km (1000 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that might
result in engine overheating must be
avoided.
EAU17094
0–1000 km (0–600 mi)
Avoid prolonged operation above 3500
r/min. NOTICE: After 1000 km (600
mi) of operation, the engine oil must
be changed and the oil filter car-
tridge or element replaced.
[ECA10303]
1000–1600 km (600–1000 mi)
Avoid prolonged operation above 4200
r/min.
1600 km (1000 mi) and beyond
The vehicle can now be operated nor-
mally.
NOTICE
ECA10311
Keep the engine speed out of
the tachometer red zone.
If any engine trouble should oc-
cur during the engine break-in
period, immediately have a
Yamaha dealer check the vehi-
cle.
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Operation and important riding points
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EAU17214
Parking
When parking, stop the engine, and
then remove the key from the main
switch.
WARNING
EWA10312
Since the engine and exhaust
system can become very hot,
park in a place where pedestri-
ans or children are not likely to
touch them and be burned.
Do not park on a slope or on soft
ground, otherwise the vehicle
may overturn, increasing the
risk of a fuel leak and fire.
Do not park near grass or other
flammable materials which
might catch fire.
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Periodic maintenance and adjustment
EAU17246
Periodic inspection, adjustment, and lu-
brication will keep your vehicle in the
safest and most efficient condition pos-
sible. Safety is an obl igation of the vehi-
cle owner/operator. The most important
points of vehicle inspection, adjust-
ment, and lubrication are explained on
the following pages.
The intervals given in the periodic
maintenance charts should be simply
considered as a general guide under
normal riding conditions. However, de-
pending on the weather, terrain, geo-
graphical location, and individual use,
the maintenance intervals may need to
be shortened.
WARNING
EWA10322
Failure to properly maintain the ve-
hicle or performing maintenance ac-
tivities incorrectly may increase
your risk of injury or death during
service or while using the vehicle. If
you are not familiar with vehicle ser-
vice, have a Yamaha dealer perform
service.
WARNING
EWA15123
Turn off the engine when performing
maintenance unless otherwise
specified.
A running engine has moving
parts that can catch on body
parts or clothing and electrical
parts that can cause shocks or
fires.
Running the engine while ser-
vicing can lead to eye injury,
burns, fire, or carbon monoxide
poisoning – possibly leading to death. See page 1-2 for more in-
formation about carbon monox-
ide.
WARNING
EWA15461
Brake discs, calipers, drums, and
linings can become very hot during
use. To avoid possible burns, let
brake components cool before
touching them.
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Periodic maintenance and adjustment
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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, replacement,
or repair of the emission control devic-
es and systems may be performed by
any repair establishment or individual
that is certified (if applicable). Yamaha
dealers are trained and equipped to
perform these particular services.
EAU59370
Owner’s tool kit
The owner’s tool kit is located inside the
tool box.
To access the owner’s tool kit, slide the
lock cover open, insert the key into the
lock, and then turn it 1/4 turn clockwise.
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.
1. Unlock.
2. Lock cover
1. Owner’s tool kit
1 2
1
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Periodic maintenance and adjustment
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EAU46862
TIP
The annual checks must be performed every year, except if a kilometer-
based maintenance, or for the UK, a mileage-based maintenance, is per-
formed instead.
From 50000 km (30000 mi), repeat the maintenance intervals starting from
10000 km (6000 mi).
Items marked with an asterisk should be performed by a Yamaha dealer as
they require special tools, data and technical skills.
EAU63321
Periodic maintenance chart for the emission control system
NO. ITEM
1 *Fuel line Check fuel hoses for cracks or
damage. 
2 Spark plug Check condition.
Clean and regap.

Replace. 
3 *Valves Check valve clearance.
Adjust. 
4 *Fuel injection Check engine idle speed. 
5 *Muffler and
exhaust pipe Check the screw clamp(s) for
looseness. 
6 *Air induction
system Check the air cut-off valve, reed
valve, and hose for damage.
Replace any damaged parts if necessary. X 1000 km
CHECK OR
MAINTENANCE JOB
X 1000 mi
ODOMETER READINGS
ANNUAL CHECK
110203040
0.66121824
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Periodic maintenance and adjustment
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13 Drive chain Check chain slack, alignment
and condition.
Adjust and lubricate chain with a special O-ring chain lubricant
thoroughly. Every 500 km (300 mi) and after
washing the motorcycle, riding
in the rain or riding in wet areas
14 *Steering bearings Check bearing play and
steering for roughness. 
Lubricate with lithium-soap- based grease. Every 20000 km (12000 mi)
15 *Chassis fasteners Make sure that all nuts, bolts
and screws are properly
tightened. 
16 Brake lever pivot
shaft Lubricate with silicone grease.

17 Brake pedal pivot
shaft Lubricate with lithium-soap-
based grease. 
18 Clutch lever pivot
shaft Lubricate with lithium-soap-
based grease. 
19 Sidestand,
centerstand Check operation.
Lubricate with lithium-soap-
based grease. 
20 *Sidestand switch Check operation. 
21 *Front fork Check operation and for oil
leakage. 
22 *Shock absorber
assemblies Check operation and shock
absorbers for oil leakage. 
23 Engine oil Change.
Check oil level and vehicle for
oil leakage. 
24 Engine oil filter
element Replace.

25 *Front and rear
brake switches Check operation.

26 Moving parts and
cables Lubricate.

NO. ITEM
X 1000 km
CHECK OR
MAINTENANCE JOB
X 1000 mi
ODOMETER READINGS
ANNUAL CHECK
110203040
0.66121824
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Periodic maintenance and adjustment
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EAU19605
Checking the spark plug
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 mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug 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 plug 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 vehicle 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 electrode erosion 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 specifica-
tion.
To install the spark plug 1. Clean the surface of the spark plug gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
2. Install the spark plug with the spark
1. Spark plug cap
1. Spark plug wrench
1
1
Specified spark plug: NGK/BPR6ES
1. Spark plug gap
Spark plug gap:0.7–0.8 mm (0.028–0.031 in)
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Periodic maintenance and adjustment
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plug wrench, and then tighten it to
the specified torque.
TIP
If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4–1/2 turn
past finger tight. However, the spark
plug should be tightened to the speci-
fied torque as soon as possible.
3. Install the spark plug cap.
EAU59626
Engine oil and oil filter
element
The engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil filter ele-
ment replaced at the intervals specified
in the periodic maintenance and lubri-
cation chart.
To check the engine oil level1. Start the engine, warm it up for several minutes, and then turn it
off.
2. On a level surface, place the vehi- cle on the centerstand.
3. Wait a few minutes until the oil set- tles. Remove the engine oil filler
cap, wipe the dipstick clean, insert
it back into the oil filler hole (with-
out screwing it in), and then re-
move it again to check the oil level.
WARNING! Never remove the
engine oil filler cap after high-
speed operation, otherwise hot
engine oil could spout out and
cause damage or injury. Always
let the engine oil cool down suf-
ficiently before removing the oil
filler cap.
[EWA17640]
TIP
The engine oil should be between the
minimum and maximum level marks.
Tightening torque:Spark plug:25 Nm (2.5 m·kgf, 18 ft·lbf)
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Periodic maintenance and adjustment
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14 4. If the engine oil is below the mini-
mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
5. Install the oil filler cap.
To change the engine oil (with or
without oil filter element replace-
ment) 1. Start the engine, warm it up for several minutes, and then turn it
off.
2. Place an oil pan under the engine to collect the used oil.
3. Remove the oil filter element cover bleed bolt and its gasket, and the
oil filter element drain bolt to drain
the oil from the oil filter element
chamber. 4. Remove the engine oil drain bolt
and its gasket to drain the oil from
the crankcase.
5. Remove the engine oil filler cap, the engine oil tank drain bolt and
its gasket to drain the oil from the
oil tank.
1. Engine oil filler cap
2. Dipstick
3. Maximum level mark
4. Minimum level mark
3
4
1
2
1. Oil filter element cover bleed bolt
2. Gasket
3. Oil filter element drain bolt
1. Gasket
2. Engine oil drain bolt (crankcase)
1
2
3
21
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Periodic maintenance and adjustment
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TIP
Skip steps 6–8 if the oil filter element is
not being replaced. 6. Remove the oil filter element cover by removing the bolts.
7. Remove and replace the oil filter element and O-rings.
TIP
Make sure that the O-rings are properly
seated. 8. Install the oil filter element cover by
installing the bolts, and then tight-
en the bolts to the specified torque.
9. Install the oil filter element drain bolt, and then tighten the bolt to the
specified torque.
10. Install the oil filter element cover bleed bolt and its gasket, and then
tighten the bolt to the specified
torque.
11. Install the engine oil drain bolts and their new gasket, and then
tighten the bolts to the specified
torques.
1. Engine oil drain bolt (oil tank)
2. Gasket
1. Oil filter element cover bolt
21
1
1. Oil filter element cover
2. O-ring
3. Oil filter element
Tightening torque:Oil filter element cover bolt: 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Tightening torque: Oil filter element drain bolt: 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Tightening torque: Oil filter element cover bleed bolt: 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
2
1
3
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