2014 YAMAHA SR400 engine

PERIODIC MAINTENANCE AND ADJUSTMENT
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EAU19605
Checking the spark plugThe 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).
TIPIf 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 checkthe 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
1. Spark plug cap
1
1. Spark plug wrench
1
Specified spark plug: NGK/BPR6ES1. Spark plug gapSpark plug gap:0.7–0.8 mm (0.028–0.031 in)
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PERIODIC MAINTENANCE AND ADJUSTMENT
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12 spark plug wrench, and then tight-
en it to the specified torque.
TIPIf 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.
EAU59622
Engine oil and oil filter
elementThe 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, other-
wise hot engine oil could spout
out and cause damage or injury.
Always let the engine oil cool
down sufficiently before remov- ing the oil filler cap.
[EWA17640]
TIPThe engine oil should be between theminimum and maximum level marks.
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.
Tightening torque: Spark plug:25 Nm (2.5 m·kgf, 18 ft·lbf)
1. Engine oil filler cap
2. Dipstick
3. Maximum level mark
4. Minimum level mark
3
4
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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. Loosen the oil filter element cover bleed bolt and oil filter element
drain bolt.
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. 6. Remove the oil filter element drain
bolt to drain the oil from the oil filter
element.
TIPSkip steps 7–9 if the oil filter element isnot being replaced.
7. Remove the oil filter element cover by removing the bolts.
8. Remove and replace the oil filter element and O-rings.TIPMake sure that the O-rings are properlyseated.
1. Oil filter element cover bleed bolt
2. Oil filter element drain bolt
1
2
1. Gasket
2. Engine oil drain bolt (crankcase)
1. Engine oil drain bolt (oil tank)
2. Gasket
21
21
1. Oil filter element drain bolt
2. Oil filter element cover bolt
2
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
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12 9. Install the oil filter element cover by
installing the bolts.
10. Install the oil filter element drain bolt.
11. Tighten the oil filter element cover bolts and the oil filter element drain
bolt to their specified torques.
12. Tighten the oil filter element cover bleed bolt to the specified torque. 13. Install the engine oil drain bolts
and their new gasket, and then
tighten the bolts to the specified
torques.
14. Add the specified amount of the recommended engine oil, and then
install and tighten the oil filler cap.
TIPBe sure to wipe off spilled oil on any
parts after the engine and exhaust sys-
tem have cooled down.NOTICE
ECA11621

In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives. Do
not use oils with a diesel speci-
fication of “CD” or oils of a high-
er quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.

Make sure that no foreign mate-rial enters the crankcase.
15. Start the engine, and then let it idle for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.
16. Turn the engine off, and then check the oil level and correct it if
necessary.
NOTICE
ECA11232
After changing the engine oil, make
sure to check the oil pressure as de-
scribed below.
1. Oil filter element cover
2. O-ring
3. Oil filter elementTightening torques:Oil filter element cover bolt:10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil filter element drain bolt:
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
2
1
3
Tightening torque:Oil filter element cover bleed bolt:5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Tightening torques: Engine oil drain bolt (crankcase):30 Nm (3.0 m·kgf, 22 ft·lbf)
Engine oil drain bolt (oil tank):
16 Nm (1.6 m·kgf, 12 ft·lbf)
Recommended engine oil: See page 8-1.
Oil quantity:
Without oil filter element replace-
ment:2.00 L (2.11 US qt, 1.76 Imp.qt)
With oil filter element replacement: 2.10 L (2.22 US qt, 1.85 Imp.qt)
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PERIODIC MAINTENANCE AND ADJUSTMENT
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
Loosen the bleed bolt.

Start the engine and keep it
idling until oil flows out. If no oil
comes out after one minute,
turn the engine off immediately
so it will not seize. If this occurs,
have a Yamaha dealer repair the
vehicle.

After checking the oil pressure,
tighten the bleed bolt to thespecified torque.
EAU52031
Replacing the air filter elementThe air filter element should be re-
placed at the intervals specified in the
periodic maintenance and lubrication
chart. Replace the air filter element
more frequently if you are riding in un-
usually wet or dusty areas.
To replace the air filter element 1. Remove panel A. (See page 6-7.)
2. Remove the air filter case cover by removing the screws.
3. Pull the air filter element out. 4. Insert a new air filter element into
the air filter case. NOTICE: Make
sure that the air filter element is
properly seated in the air filter
case. The engine should never
be operated without the air filter
element installed, otherwise the
piston(s) and/or cylinder(s) may
become excessively worn.
[ECA10482]
5. Install the air filter case cover by in- stalling the screws.
6. Install the panel.
1. Bleed boltTightening torque: Bleed bolt: 18 Nm (1.8 m·kgf, 13 ft·lbf)
1
1. Screw
2. Air filter case cover
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2
1
1. Air filter element
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
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EAU44735
Checking the engine idling
speedCheck the engine idling speed and, if
necessary, have it corrected by a
Yamaha dealer.
EAU21385
Checking the thrott le grip free
playThe throttle grip free play should mea-
sure 3.0–5.0 mm (0.12–0.20 in) at the
inner edge of the throttle grip. Periodi-
cally check the throttle grip free play
and, if necessary, have a Yamaha
dealer adjust it.
EAU21402
Valve clearanceThe valve clearance changes with use,
resulting in improper air-fuel mixture
and/or engine noise. To prevent this
from occurring, the valve clearance
must be adjusted by a Yamaha dealer
at the intervals specified in the periodic
maintenance and lubrication chart.
Engine idling speed: 1200–1400 r/min
1. Throttle grip free play
1
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PERIODIC MAINTENANCE AND ADJUSTMENT
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12 gine as well as other vital parts
of the motorcycle and can lead
to chain slippage or breakage.
To prevent this from occurring,
keep the drive chain slack with-
in the specified limits.
[ECA10572]
TIPUsing the alignment marks on each
side of the swingarm, make sure that
both drive chain pullers are in the sameposition for proper wheel alignment.
6. Take the motorcycle off the center- stand, and then put the sidestand down.
7. Tighten both drive chain puller locknuts, and then tighten the axle
nut and brake torque rod nut to
their specified torques.
8. Adjust the brake pedal free play. (See page 6-18.)
WARNING
EWA10661
After adjusting the brake pedal free
play, check the operation of thebrake light.
9. Make sure that the drive chain pull- ers are in the same position, the
drive chain slack is correct, and
the drive chain moves smoothly.
EAU23026
Cleaning and lubricating the
drive chainThe drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.NOTICE
ECA10584
The drive chain must be lubricated
after washing the motorcycle, ridingin the rain or riding in wet areas.
1. Clean the drive chain with kero- sene and a small soft brush.
NOTICE: To prevent damaging
the O-rings, do not clean the
drive chain with steam cleaners,
high-pressure washers or inap-
propriate solvents.
[ECA11122]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain
lubricant. NOTICE: Do not use
engine oil or any other lubri-
cants for the drive chain, as they
1. Axle nut
2. Drive chain puller locknut
3. Drive chain slack adjusting bolt
4. Alignment marks
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(a) (b)
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Tightening torques:
Drive chain puller locknut:16 Nm (1.6 m·kgf, 12 ft·lbf)
Axle nut: 129 Nm (12.9 m·kgf, 92 ft·lbf)
Brake torque rod nut:
19 Nm (1.9 m·kgf, 14 ft·lbf)
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EAU60030
Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the battery.
Supply fuel.
The engine does not start.
Check the battery.
Operate the kickstarter.4. Compression
There is compression.
There is no compression.
Have a Yamaha dealer check the vehicle.The engine does not start.
Have a Yamaha dealer check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug. Have a Yamaha dealer check the vehicle.
The engine does not start.
Check the compression.
Operate the kickstarter.
If the engine does not
start, check the ignition.
With the key in the on
position, operate the turn
signal switch.2. Battery
The turn signal flashes
brightly.
The turn signal does
not flash or is weak.
The battery is good.Check the battery lead connections,
and have a Yamaha dealer charge
the battery if necessary.
DryWet
Operate the kickstarter.
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