THROTTLE BODY

Removing the throttle body

Order

Job/Parts to remove

Q’ty

Remarks

 

Seat/Air filter case cover

 

Refer to GENERAL CHASSIS.

 

Side cover (left/right)

 

Refer to GENERAL CHASSIS.

 

Air scoop (left/right)

 

Refer to GENERAL CHASSIS.

 

Fuel tank

 

Refer to FUEL TANK.

1

ECU (Engine Control Unit)

1

 

2

Ignition coil

1

 

3

Intake air temperature sensor coupler

1

Disconnect.

4

Air filter case

1

 

5

Fuel injector coupler

1

Disconnect.

6

Intake air pressure sensor coupler

1

Disconnect.

7

Throttle position sensor coupler

1

Disconnect.

8

Cover

1

 

9

Throttle cable cover

1

 

10

Throttle cable

2

 

11

Fuel hose

1

 

12

Throttle body

1

 

Removing the throttle body

Order

Job/Parts to remove

Q’ty

Remarks

13

Exhaust pipe bracket

1

 

14

Throttle body joint

1

 

Removing the injector

Order

Job/Parts to remove

Q’ty

Remarks

1

Fuel inlet pipe

1

 

2

Injector

1

 

3

Gasket

1

 

4

Throttle position sensor

1

 

5

Intake air pressure sensor

1

 

CHECKING THE INJECTOR

1.Check:

  • Injector

    Obstruction → Replace, and check the fuel pump and the fuel injection system.

    Refer to FUEL INJECTION SYSTEM.

    Deposits → Replace.

    Damage → Replace.

2.Check:

CHECKING THE THROTTLE BODY

1.Check:

  • Throttle body

    Cracks/damage → Replace.

2.Check:

  • Fuel passages

    Obstructions → Clean.

  • Before removing the throttle body, clean the area around the throttle body to prevent dirt and other foreign material from falling into the engine.

  • If the throttle body is subject to strong shocks or dropped during cleaning, replace it.

  • Do not use any caustic carburetor cleaning solution.

  • Do not directly push the throttle valves to open them.

  • Do not loosen the throttle valve stopper screw “1”, throttle valve pulley nut “2”, throttle valve screw “3” or starter knob nut “4”. A loss of performance may occur.

  • Do not use compressed air to clean the throttle body. Foreign materials may adhere to the intake air pressure sensor passage “a” and fuel injector “b” in the throttle body.

3.Check:

  • Idle screw “1” passage “a”

    Obstruction → Blow out with compressed air.

CHECKING THE FUEL PRESSURE

1.Check:

  • Fuel pressure

a.Remove the side cover (left/right), the seat and the air scoop (left/right).

Refer to GENERAL CHASSIS.

b.Remove the fuel tank bolt and lift the fuel tank.

c.Disconnect the fuel hose from the fuel pump.

Refer to REMOVING THE FUEL TANK.

Cover the fuel hose connection with a cloth when disconnecting it. This is because residual pressure in the fuel hose could cause fuel to spurt out when the hose is removed.

Make sure that the fuel hose is disconnected by hand. Do not forcibly disconnect the hose with tools.

d.Connect the pressure gauge “1” and the fuel pressure adapter “2” to the fuel hose.

  • Pressure gauge

    90890-03153

  • Pressure gauge

    YU-03153

  • Fuel pressure adapter

    90890-03186

  • Fuel pressure adapter

    YM-03186

e.Start the engine.

f.Measure the fuel line pressure.

Out of specification → Replace the fuel pump.

  • Fuel line pressure (at idle)

    300–390 kPa (3.0–3.9 kgf/cm², 43.5–56.6 psi)

ADJUSTING THE THROTTLE POSITION SENSOR

  • Handle the throttle position sensor with special care.

  • Never subject the throttle position sensor to strong shocks. If the throttle position sensor is dropped, replace it.

1.Check:

2.Adjust:

  • Throttle position sensor angle

a.Connect the Yamaha diagnostic tool.

Refer to YAMAHA DIAGNOSTIC TOOL.

  • Yamaha diagnostic tool USB (US)

    90890-03269

  • Yamaha diagnostic tool (A/I)

    90890-03264

  • FI diagnostic tool sub–lead

    90890-03212

  • FI diagnostic tool sub–lead

    YU-03212

  • OBD/ GST Leadwire kit

    90890-03249

b.Temporary tighten the throttle position sensor.

c.Check that the throttle grip is fully closed.

d.Connect the throttle position sensor to the wire harness.

e.Set the Yamaha diagnostic tool to “diagnostic mode”.

f.Choose the diagnostic code No. “01”.

g.Adjust the throttle position sensor mounted angle until “11”–“14” appears on the Yamaha diagnostic tool.

h.After adjusting the throttle position sensor mounted angle, tighten the throttle position sensor screw “1”.

  • Throttle position sensor screw

    3.5 N·m (0.35 kgf·m, 2.6 lb·ft)