(II) Engine Ground

←→ Battery (–) Terminal

Criteria:
Both: 0 Ω

If no continuity, check the connectors, the engine ground
lead, or main harness, and repair or replace them if necessary.
If the wiring is good, check the power source voltage of
the ECU.

NOTE

○Be sure the battery is fully charged.
the ECU connectors.
• Connect
Connect
a digital meter [A] to the connector (black) [B]
• with the needle
adapter set.
Special Tool - Needle Adapter Set: 57001-1457
ECU Power Supply Inspection
Connections:
(I) Digital Meter (+) → BR/W lead (terminal 6)
Digital Meter (–) → Battery (–) Terminal
(II) Digital Meter (+) → W/BK lead (terminal 7)
Digital Meter (–) → Battery (–) Terminal
Ignition Switch off:
BR/W lead (terminal 6): 0 V
W/BK lead (terminal 7): Battery Voltage
Ignition Switch on:
Both: Battery Voltage

If the reading is out of the specification, check the following.
Main Fuse 30 A (see Fuse Inspection in the Electrical
System chapter)
ECU Fuse 15 A (see Fuse Inspection in the Electrical
System chapter)
ECU Main Relay (see Relay Circuit Inspection in the
Electrical System chapter)
Power Source Wiring (see ECU Power Source Circuit)
If the fuse, wiring and relay are good, replace the ECU
(see ECU Removal/Installation).

FUEL SYSTEM (DFI) 3-111
ECU
ECU Power Source Circuit

1. Ignition Switch
2. Fuse Box (1)
3. Ignition Fuse 15 A
4. ECU
5. Joint Connector B
6. Engine Ground
7. Battery 12 V 8 Ah
8. Starter Relay
9. Main Fuse 30 A
10. ECU Fuse 15 A
11. Relay Box
12. ECU Main Relay
13. Frame Ground (9)
14. Frame Ground (7)
15. Frame Ground (6)

3-112 FUEL SYSTEM (DFI)
DFI Power Source
ECU Fuse Removal

to the 30 A Main/15 A ECU Fuse Removal in the
• Refer
Electrical System chapter.

ECU Fuse Installation

•

If a fuse fails during operation, inspect the DFI system to
determine the cause, and then replace it with a new fuse
of proper amperage.
Refer to the Fuse Installation in the Electrical System
chapter.

ECU Fuse Inspection

to the Fuse Inspection in the Electrical System
• Refer
chapter.

ECU Main Relay Removal/Installation

○The ECU main relay is built in the relay box [A].

to the Relay Box Removal in the Electrical System
• Refer
chapter.

ECU Main Relay Inspection

to the Relay Circuit Inspection in the Electrical Sys• Refer
tem chapter.

FUEL SYSTEM (DFI) 3-113
Fuel Line
Fuel Pressure Inspection
NOTE

○Be sure the battery is fully charged.

• Remove:
Fuel Hose (see Fuel Hose Replacement in the Periodic
Maintenance chapter)
○Be sure to place a piece of cloth around the fuel outlet
pipe of the fuel pump and the delivery pipe of the throttle
body assy.

WARNING
Fuel is flammable and explosive under certain conditions and can cause severe burns. Be prepared
for fuel spillage; any spilled fuel must be completely
wiped up immediately. When the fuel hose is disconnected, fuel spills out from the hose and the
pipe because of residual pressure. Cover the hose
connection with a piece of clean cloth to prevent
fuel spillage.
the fuel pressure gauge adapter [A] and fuel hoses
• Install
(Special Tool: 57001-1607) [B] between the fuel outlet

•
•

pipe and delivery pipe.
Secure the fuel hoses with the clamps.
Connect the pressure gauge [C] to the fuel pressure
gauge adapter.
Special Tools - Oil Pressure Gauge, 5 kgf/cm²: 57001-125
Fuel Pressure Gauge Adapter: 57001-1593
Fuel Hose: 57001-1607

WARNING
Fuel is extremely flammable and can be explosive
under certain conditions resulting in serious injury
or death. Do not try to start the engine with the fuel
hoses disconnected.
the fuel tank temporarily (see Fuel Tank Installa• Install
tion).
the engine stop switch to run position.
• Turn
Turn
the ignition switch on.
•○The fuel
pump should operate for 3 seconds, and then
should stop.

○After

NOTE

turning on the engine stop switch and ignition
switch, inspect the fuel leakage from the connected
portion of the special tools.

NOTICE
Do not drive the fuel pump 3 seconds or more without the fuel in the fuel tank. If the fuel pump is driven
without the fuel, it may be damaged.

3-114 FUEL SYSTEM (DFI)
Fuel Line
the engine, and let it idle.
• Start
Measure
the fuel pressure with the engine idling.
•
Fuel Pressure (with Engine Idling)
Standard: 294 kPa (3.0 kgf/cm², 43 psi)

NOTE

○The gauge needle will fluctuate.

Read the pressure at
the average of the maximum and minimum indications.

the ignition switch off.
• Turn
If the fuel pressure is much higher than specified, replace

•
•
•
•

the fuel pump because the fuel pressure regulator in the
fuel pump have been clogged or stuck.
If the fuel pressure is much lower than specified, check
the following.
Fuel Line Leakage (see Fuel Injector Fuel Line Inspection)
Amount of Fuel Flow (see Fuel Flow Rate Inspection)
After above checks, measure the fuel pressure again.
Remove the fuel pressure gauge, hoses and adapter.
Install:
Fuel Hose (see Fuel Hose Replacement in the Periodic
Maintenance chapter)
Start the engine and check for fuel leakage.

Fuel Flow Rate Inspection

WARNING
Gasoline is extremely flammable and can be explosive under certain conditions, creating the potential
for serious burns. Make sure the area is well ventilated and free from any source of flame or sparks;
this includes any appliance with a pilot light. Do not
smoke. Turn the ignition switch off. Be prepared for
fuel spillage; any spilled fuel must be completely
wiped up immediately.

NOTE

○Be sure the battery is fully charged.
the ignition switch off.
• Turn
Wait
until
cools down.
• Prepare athefuelengine
hose
• measuring cylinder. (Special Tool:

57001-1607) and a

Special Tool - Fuel Hose: 57001-1607

FUEL SYSTEM (DFI) 3-115
Fuel Line
the fuel tank cap [A] to lower the pressure in the
• Open
tank.
the fuel hose from the fuel pump (see Fuel
• Disconnect
Tank Removal).

○Be sure to place a piece of cloth around the fuel outlet
pipe of the fuel pump.

WARNING
Fuel is flammable and explosive under certain conditions and can cause severe burns. Be prepared
for fuel spillage; any spilled fuel must be completely
wiped up immediately. When the fuel hose is disconnected, fuel spills out from the hose and the
pipe because of residual pressure. Cover the hose
connection with a piece of clean cloth to prevent
fuel spillage.
the prepared fuel hose [A] to the fuel outlet pipe.
• Connect
the fuel hose with a clamp.
• Secure
Insert
the
fuel hose into the measuring cylinder [B].
•

WARNING
Wipe off spilled out fuel immediately.
Be sure to hold the measuring cylinder vertical.
the fuel tank cap.
• Close
Turn
the
stop switch to run position.
• Turn the engine
ignition
switch on.
•○The fuel pump should
operate for 3 seconds, and then
should stop.

NOTICE
Do not drive the fuel pump 3 seconds or more without the fuel in the fuel tank. If the fuel pump is driven
without the fuel, it may be damaged.
the discharge for 3 seconds.
•○Measure
Repeat this operation several times.
Amount of Fuel Flow
Standard: 50 mL (1.7 US oz.) or more for 3 seconds

the ignition switch off.
• Turn
If the fuel flow is much less than the specified, replace the

•
•

fuel pump (see Fuel Pump Removal/Installation).
Install the fuel tank (see Fuel Tank Installation).
Start the engine and check for fuel leakage.

3-116 FUEL SYSTEM (DFI)
Fuel Pump
Fuel Pump Removal

WARNING
Gasoline is extremely flammable and can be explosive under certain conditions, creating the potential
for serious burns. Make sure the area is well ventilated and free from any source of flame or sparks;
this includes any appliance with a pilot light. Do not
smoke. Turn the ignition switch off. Disconnect the
battery (–) terminal. To avoid fuel spills, draw it from
the tank when the engine is cold. Be prepared for
fuel spillage; any spilled fuel must be completely
wiped up immediately.

NOTICE
Never drop the fuel pump especially on a hard surface. Such a shock to the pump can damage it.
the fuel out from the fuel tank with a commercially
• Draw
available electric pump.
the fuel tank (see Fuel Tank Removal).
•○Remove
Be careful of fuel spillage from the fuel tank since fuel still
remains in the fuel tank and fuel pump. Plug the fuel pipe
of the fuel tank.
the fuel tank upside down.
• Turn
Remove
• pump [B].the fuel pump bolts [A], and take out the fuel

NOTICE
Do not pull the leads of the fuel pump. If they are
pulled, the lead terminals may be damaged.

• Discard the fuel pump gasket [A].

FUEL SYSTEM (DFI) 3-117
Fuel Pump
Fuel Pump Installation

dirt or dust from the fuel pump [A] by lightly ap• Remove
plying compressed air.
the fuel pump gasket with a new one.
• Replace
Apply
grease
to the fuel pump gasket.
•

NOTE

○Be careful not to bend the fuel level sensor arm.
that the fuel pump terminal [A] and band [B] are in
• Check
place.
a non-permanent locking agent to the threads of
• Apply
the fuel pump bolts.
the fuel pump bolts [C] to a snug fit.
• Tighten
Tighten
the
fuel pump bolts alternating diagonally.
•
Torque - Fuel Pump Bolts: 9.8 N·m (1.0 kgf·m, 87 in·lb)

• Tighten the pump bolts again to check the tightness.
Fuel Pump Operation Inspection
NOTE

○Be sure the battery is fully charged.
the engine stop switch to run position.
• Turn
Turn
ignition switch on and make sure that the fuel
• pumptheoperates
(make light sounds) for 3 seconds, and

•

then stops.
Turn the ignition switch off.
If the pump does not operate as described above, check
the operating voltage (see Fuel Pump Operating Voltage
Inspection).

3-118 FUEL SYSTEM (DFI)
Fuel Pump
Fuel Pump Operating Voltage Inspection
NOTE

○Be sure the battery is fully charged.
the ignition switch off.
• Turn
Remove
the front seat (see Front Seat Removal in the
• Frame chapter).
the fuel pump lead connector and connect
• Disconnect
the measuring adapter [A] between these connectors as
shown.
Main Harness [B]
Fuel Pump [C]
Special Tool - Measuring Adapter: 57001-1700

a digital meter [D] to the measuring adapter
• Connect
leads.
Fuel Pump Operating Voltage
Connections to Adapter:
Digital Meter (+) → R (pump BK/Y) lead
Digital Meter (–) → BK (pump BK/W) lead

the operating voltage with engine stopped and
• Measure
with the connector joined.
the engine stop switch to run position.
• Turn
Turn
• the ignition switch on.
Operating Voltage
Standard: Battery Voltage for 3 seconds, and then 0 V

the ignition switch off.
• Turn
If the reading stays on battery voltage and never shows 0
V, check the fuel pump relay (see Relay Circuit Inspection
in the Electrical System chapter).
If the fuel pump relay is normal, check the ECU for its
ground and power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).
If there is still no battery voltage, check the fuel pump relay (see Relay Circuit Inspection in the Electrical System
chapter).
If the fuel pump relay is normal, check the wiring for continuity (see Fuel Pump Circuit).
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).
If the reading is in specification, but the pump does not operate, replace the fuel pump (see Fuel Pump Removal/Installation).

FUEL SYSTEM (DFI) 3-119
Fuel Pump
Pressure Regulator Removal

○The pressure regulator [A] is built into the fuel pump [B]
and can not be removed.

Fuel Pump Relay Removal/Installation

○The fuel pump relay is built in the relay box [A].

to the Relay Box Removal in the Electrical System
• Refer
chapter.

Fuel Pump Relay Inspection

to the Relay Circuit Inspection in the Electrical Sys• Refer
tem chapter.

3-120 FUEL SYSTEM (DFI)
Fuel Pump
Fuel Pump Circuit

1. Ignition Switch
2. Fuse Box (1)
3. Ignition Fuse 15 A
4. Engine Stop Switch
5. ECU
6. Fuel Pump
7. Frame Ground (2)
8. Engine Ground
9. Battery 12 V 8 Ah
10. Starter Relay
11. Main Fuse 30 A
12. ECU Fuse 15 A
13. Relay Box
14. Fuel Pump Relay
15. Frame Ground (9)

FUEL SYSTEM (DFI) 3-121
Throttle Grip and Cables
Free Play Inspection

to the Throttle Control System Inspection in the Pe• Refer
riodic Maintenance chapter.

Free Play Adjustment

to the Throttle Control System Inspection in the Pe• Refer
riodic Maintenance chapter.

Cable Installation

the throttle cables in accordance with the Cable,
• Install
Wire, and Hose Routing section in the Appendix chapter.
the lower ends of the throttle cables in the throttle
• Install
pulley on the throttle body assy after installing the upper

•

ends of the throttle cables in the grip.
After installation, adjust each cable properly (see Throttle
Control System Inspection in the Periodic Maintenance
chapter).

WARNING
Operation with incorrectly routed or improperly adjusted cables could result in an unsafe riding condition. Be sure the cables are routed correctly and
properly adjusted.

Cable Lubrication

to the Chassis Parts Lubrication in the Periodic
• Refer
Maintenance chapter.

3-122 FUEL SYSTEM (DFI)
Throttle Body Assy
Idle Speed Inspection/Adjustment

to the Idle Speed Inspection/Adjustment in the Pe• Refer
riodic Maintenance chapter.

Synchronization Inspection/Adjustment

to the Engine Vacuum Synchronization Inspection
• Refer
in the Periodic Maintenance chapter.

Throttle Body Assy Removal

WARNING
Gasoline is extremely flammable and can be explosive under certain conditions, creating the potential
for serious burns. Make sure the area is well ventilated and free from any source of flame or sparks;
this includes any appliance with a pilot light. Do not
smoke. Turn the ignition switch off. Be prepared for
fuel spillage; any spilled fuel must be completely
wiped up immediately.

NOTICE
Never drop the throttle body assy especially on a
hard surface. Such a shock to the body assy can
damage it.

• Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal)
Fuel Hose (see Fuel Hose Replacement in the Periodic
Maintenance chapter)

• Disconnect:
Intake Air Pressure Sensor #1 Connector [A]
•

Intake Air Pressure Sensor #2 Connector [B]
Subthrottle Valve Actuator Connector [C]
Main Throttle Sensor Connector [D]
Subthrottle Sensor Connector [E]
Disconnect the vacuum hose [F].

the locknuts [A].
• Loosen
Turn
the
adjusters [B] to give the more free play.
•

FUEL SYSTEM (DFI) 3-123
Throttle Body Assy

• Loosen the throttle body assy holder clamp bolts [A].
Special Tool - Carburetor Drain Plug Wrench, Hex 3:
57001-1269

the throttle body assy [A] from the throttle body
• Remove
assy holders.
the fuel injector connectors [B].
• Disconnect
Remove
the
clamps [C] from the delivery pipe.
•

• Remove:
Throttle Cable Holder Clamp [A]
Throttle Cable Lower Ends [B]
Throttle Body Assy [C]

removing the throttle body assy, stuff pieces of lint
• After
-free, clean cloth into the throttle body assy holders.

NOTICE
If dirt gets into the engine, excessive engine wear
and possible engine damage will occur.

Throttle Body Assy Installation