2016 YAMAHA SR400 compression ratio

Table of contents
Safety information............................ 1-1
Description ........................................ 2-1
Left view .......................................... 2-1
Right view ........................................ 2-2
Controls and instruments ................ 2-3
Instrument and control functions ... 3-1
Main switch/steering lock ................ 3-1
Indicator lights and warning lights ... 3-2
Speedometer unit ..... ....................... 3-3
Tachometer ..................................... 3-4
Handlebar switches ......................... 3-4
Clutch lever ..................................... 3-6
Shift pedal ....................................... 3-6
Brake lever ...................................... 3-7
Brake pedal .............. ....................... 3-7
Fuel tank cap ................................... 3-8
Fuel ................................................. 3-9
Fuel tank breather/overflow hose ........................................... 3-10
Catalytic converter......................... 3-11
Fuel cock ....................................... 3-11
Kickstarter .... ............................. .... 3-12
Decompression lever..................... 3-12
Seat ............................................... 3-13
Adjusting the shock absorber assemblies ................................. 3-13
Sidestand ...................................... 3-14
Ignition circuit cut- off system ......... 3-15
For your safety – pre-operation
checks ................................................ 4-1
Operation and im portant riding
points ................................................. 5-1
Starting the engine .......................... 5-2
Starting trouble ................................ 5-3
Shifting ............................................ 5-3
Tips for reducing fuel consumption................................. 5-5
Engine break-in ............................... 5-5
Parking ............................................ 5-6 Periodic maintenance and
adjustment
........................................ 6-1
Owner’s tool kit ............................... 6-2
Periodic maintenance chart for the
emission control system .............. 6-3
General maintenance and lubrication chart ........................... 6-4
Removing and installing the panel ............................................ 6-7
Checking the spark plug ................. 6-8
Engine oil and oil filter element ....... 6-9
Replacing the air filter element ..... 6-13
Checking the engine idling
speed ......................................... 6-14
Checking the throttle grip free play ............................................ 6-14
Valve clearance ............................ 6-15
Tires .............................................. 6-15
Spoke wheels........... ..................... 6-17
Adjusting the clutch lever free play ............................................ 6-18
Adjusting the brake lever free play ............................................ 6-19
Adjusting the brake pedal height
and free play .............................. 6-20
Checking the shift pedal................ 6-21
Brake light switches ...................... 6-22
Checking the front brake pads and rear brake shoes ................ 6-22
Checking the brake fluid level ....... 6-23
Changing the brake fluid .............. 6-24
Drive chain slack ........................... 6-25
Cleaning and lubricating the drive
chain .......................................... 6-26
Checking and lubricating the cables ........................................ 6-27
Checking and lubricating the throttle grip and ca ble ................ 6-27
Checking and lubricating the
brake and clutch levers.............. 6-28
Checking and lubricating the brake pedal ................................ 6-28
Checking and lubricating the centerstand and sidestand ........ 6-29
Lubricating the swingarm pivots.... 6-29
Checking the front fork .................. 6-30
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Operation and important riding points
5-2
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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
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Operation and important riding points
5-3
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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
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Periodic maintenance and adjustment
6-4
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EAU64031
General maintenance and lubrication chart
NO. ITEM
1 Air filter element Replace. Every 20000 km (12500 mi)
2Clutch Check operation.
Adjust. 
3 *Timing chain Check timing chain tensioner.
Adjust if necessary. 
4 *Decompression
system Check operation.
Adjust or replace cable.

5 *Front brake Check operation, fluid level and
vehicle for fluid leakage.
Adjust brake lever free play. 
Replace brake pads. Whenever worn to the limit
6 *Rear brake Check operation and adjust
brake pedal free play. 
Replace brake shoes. Whenever worn to the limit
7 *Brake hose Check for cracks or damage.
Check for correct routing and
clamping. 
Replace. Every 4 years
8 *Brake fluid Change. Every 2 years
9 *Wheels Check runout, spoke tightness
and for damage.
Tighten spokes if necessary. 
10 *Tires Check tread depth and for
damage.
Replace if necessary.
Check air pressure.
Correct if necessary. 
11 *Wheel bearings Check bearings for looseness
or damage. 
12 *Swingarm Check operation and for
excessive play. 
Lubricate with lithium-soap- based grease. Every 50000 km (30000 mi)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
6-42
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EAU25852
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur dur-
ing operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting chart
represents a quick and easy procedure
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look like
Yamaha parts, but they are often inferi-
or, have a shorter service life and can
lead to expensive repair bills.
WARNING
EWA15142
When checking the fuel system, do
not smoke, and make sure there are
no open flames or sparks in the ar-
ea, including pilot lights from water
heaters or furnaces. Gasoline or
gasoline vapors can ignite or ex-
plode, causing severe injury or
property damage.
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8-1
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Specifications
EAU69993Dimensions:
Overall length: 2085 mm (82.1 in)
Overall width: 750 mm (29.5 in)
Overall height:
1095 mm (43.1 in)
Seat height: 785 mm (30.9 in)
Wheelbase: 1410 mm (55.5 in)
Ground clearance:
130 mm (5.12 in)
Minimum turning radius: 2.4 m (7.87 ft)
Weight:
Curb weight:
174 kg (384 lb)
Engine:
Combustion cycle:4-stroke
Cooling system:
Air cooled
Valve train: SOHC
Number of cylinders: Single cylinder
Displacement:
399 cm
3
Bore  stroke:
87.0  67.2 mm (3.43  2.65 in)
Compression ratio: 8.5 : 1
Starting system:
Kickstarter
Lubrication system: Dry sump
Engine oil:
Recommended brand:
YAMALUBE
SAE viscosity grades: 10W-40
Recommended engine oil grade:
API service SG type or higher, JASO stan-
dard MA
Engine oil quantity:
Oil change:2.00 L (2.11 US qt, 1.76 Imp.qt)
With oil filter removal:
2.10 L (2.22 US qt, 1.85 Imp.qt)
Air filter:
Air filter element:Oil-coated paper element
Fuel:
Recommended fuel:
Regular unleaded gasoline (Gasohol [E10]
acceptable)
Fuel tank capacity:
12 L (3.2 US gal, 2.6 Imp.gal)
Fuel reserve amount: 2.2 L (0.58 US gal, 0.48 Imp.gal)
Fuel injection:
Throttle body:
ID mark: 2RD1 00
Spark plug(s):
Manufacturer/model:NGK/BPR6ES
Spark plug gap: 0.7–0.8 mm (0.028–0.031 in)
Clutch:
Clutch type:Wet, multiple-disc
Drivetrain:
Primary reduction ratio:
2.567 (77/30)
Final drive: Chain
Secondary reduction ratio: 2.947 (56/19)
Transmission type:
Constant mesh 5-speed
Gear ratio: 1st:
2.357 (33/14)
2nd: 1.556 (28/18)
3rd: 1.190 (25/21)
4th: 0.917 (22/24)
5th: 0.778 (21/27)
Chassis:
Frame type:Semi double cradle
Caster angle: 27.7 
Trail:
111 mm (4.4 in)
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