2000 YAMAHA WR 400F fuel

5 - 44
CHASHANDLEBAR
NOTE:
lThe “ENGINE STOP” button, clutch lever
holder and clamp should be installed accord-
ing to the dimensions shown.
lPass the “ENGINE STOP” button lead in the
middle of the clutch holder.
9. Install:
lClutch cable 1
NOTE:
Apply the lithium soap base grease on the
clutch cable end.
10. Adjust:
lClutch lever free play
Refer to “CLUTCH ADJUSTMENT”
section in the CHAPTER 3.
11. Insert the end of the fuel breather hose
1 into the hole of the steering shaft.

5 - 58
CHASREAR SHOCK ABSORBER
EC580000
REAR SHOCK ABSORBER
Extent of removal:1 Rear shock absorber removal2 Rear shock absorber disassembly
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR SHOCK ABSORBER
REMOVAL
Hold the machine by placing the
suitable stand under the engine.
Seat, fitting band and side covers Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
Silencer Refer to “EXHAUST PIPE AND
SILENCER” section in the CHAPTER 4.
Drain the coolant. Refer to “COOLANT REPLACENENTR ”
section in the CHAPTER 3.
Coolant reservoir Refer to “RADIATOR” section in the
CHAPTER 4.
1 Tail light connector 2
2 Band 2
3 Bolt (brake reservoir tank) 1
4 Clamp (air cleaner joint) 1 Only loosening.
5 Rear frame 1
6 Bolt (rear shock absorber-relay arm) 1Hold the swingarm.
7 Bolt (rear shock absorber-frame) 1
8 Rear shock absorber 1
WARNING
Support the machine securely so there is nodanger of it falling over.
1
2

6 - 3
–+ELEC

IGNITION SYSTEM
EC620000
IGNITION SYSTEM
EC621001
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to
ignition system failure and for checking the spark plug which will not spark.
*: Only when the ignition checker is used.
NOTE:

l
Remove the following parts before inspection.
1) Seat
2) Fuel tank
l
Use the following special tools in this inspection.
Spark gap test*Clean or replace
spark plug.
Check entire ignition
system for connection.Repair or replace.
Check “ENGINE STOP”
button.Replace.
Check ignition coil. Primary coil Replace.
Secondary coilReplace.
Check CDI magneto. Pick-up coil Replace.
Source coil Replace.
Check neutral switch. Repair or replace.
Replace CDI unit.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-03112/90890-03112
No Spark
OK
OK
OK
OK
Spark
No good
No good
No good
No good
No good
No good
No good
OK

6 - 7
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
EC69000
TPS (THROTTLE POSITION SENSOR) SYSTEM
EC691000
INSPECTION STEPS
If the TPS will not operate, use the following inspection steps.
*marked: Refer to “IGNITION SYSTEM” section.
NOTE:
lRemove the following parts before inspection.
1) Seat
2) Fuel tank
lUse the following special tools in this inspection.
Check entire ignition
system for connection.Repair or replace.
Check TPS. TPS coil Replace.
*Check CDI magneto. Source coil Replace.
Check CDI unit.TPS input
voltageReplace.
Pocket tester:
YU-03112/90890-03112Inductive tachometer:
YU-8036-1
Engine tachometer:
90890-03113
No good
No good
No good
No good
OK
OK
OK

6 - 11
–+ELECLIGHTING SYSTEM
LIGHTING SYSTEM
INSPECTION STEPS
Refer to the following flow chart when inspecting the ignition system for possible ploblems.
NOTE:
lReplace the bulb and/or bulb socket.
1) Seat
2) Fuel tank
lUse the following special tool.
Check the bulb and bulb
socket.Replace the bulb
and/or bulb socket.
Check the lights switch. Replace.
Check the CDI magneto. Lighting coil Replace.
Check the entire lighting sys-
tem proper for connections.Repair or replace.
Replace the regulator.
Pocket tester:
YU-03112/90890-03112
OK
OK
OK
OK
No good
No good
Improperly connected
No good

7 - 1
TUN

EC700000
TUNING
EC710000
ENGINE
Carburetor setting
l
The air/fuel mixture will vary depending on
atmospheric conditions. Therefore, it is nec-
essary to take into consideration the air pres-
sure, ambient temperature, humidity, etc.,
when adjusting the carburetor.
l
Perform a test run to check for proper engine
performance (e.g., throttle response) and
spark plug(-s) discoloration or fouling. Use
these readings to determine the best possi-
ble carburetor setting.
NOTE:

It is recommended to keep a record of all car-
buretor settings and external conditions (e.g.,
atmospheric conditions, track/surface condi-
tions, lap times) to make future carburetor set-
ting easier.
WARNING

l
The carburetor is a part of the fuel line.
Therefore, be sure to install it in a well-
ventilated area, away from flammable
objects and any sources of fire.
l
Never look into the carburetor intake.
Flames may shoot out from the pipe if the
engine backfires while it is being started.
Gasoline may be discharged from the
accelerator pump nozzle when the carbu-
retor has been removed.
CAUTION:

l
The carburetor is extremely sensitive to
foreign matter (dirt, sand, water, etc.).
During installation, do not allow foreign
matter to get into the carburetor.
l
Always handle the carburetor and its
components carefully. Even slight
scratches, bends or damage to carbure-
tor parts may prevent the carburetor from
functioning correctly. Carefully perform
all servicing with the appropriate tools
and without applying excessive force.
l
When the engine is stopped or when
riding at no load, do not open and close
the throttle unnecessarily. Otherwise, too
much fuel may be discharged, starting
may become difficult or the engine may
not run well.
SETTING
7

7 - 2
TUN

l
After installing the carburetor, check that
the throttle operates correctly and opens
and closes smoothly.
Atmospheric conditions and carburetor
settings
The air density (i.e., concentration of oxygen
in the air) determines the richness or lean-
ness of the air/fuel mixture. Therefore, refer
to the above table for mixture settings.
That is:
l
Higher temperature expands the air with its
resultant reduced density.
l
Higher humidity reduces the amount of oxy-
gen in the air by so much of the water vapor
in the same air.
l
Lower atmospheric pressure (at a high alti-
tude) reduces the density of the air.
Air temp. HumidityAir
pressure
(altitude)Mixture Setting
High High Low (high) Richer Leaner
Low Low High (low) Leaner Richer
SETTING
Effects of the setting parts on the throttle
valve opening

Closed
õ
Fully open
4/4
3/4
1/2
1/4
1/8
0õ


1/2 3/4 1/4 1/8
AB
1
2
3
4

1
Pilot screw/Pilot jet
2
Piston valve cutaway
3
Jet needle
4
Main jet

7 - 3
TUN

SETTING
Main system
The FLATCR carburetor has a primary main
jet. This type of main jet is perfect for racing
motorcycles since it supplies an even flow of
fuel, even at full load. The main air jet has
almost no effect on the air-fuel mixture. Use
the main jet and the jet needle to set the car-
buretor.
1
Jet needle
2
Main air jet
3
Pilot air jet
4
Needle jet
5
Main jet
6
Pilot jet
7
Pilot screw
Pilot system
The FLATCR carburetor is manufactured with
a pilot screw. The adjusting range of the pilot
screw is limited by the throttle opening during
idling.