THROTTLE BODY

Removing the throttle body
Order	Job/Parts to remove	Q’ty	Remarks
	Seat		Refer to GENERAL CHASSIS.
	Side cover (left/right)		Refer to GENERAL CHASSIS.
	Shroud (left/right)		Refer to GENERAL CHASSIS.
	Fuel tank		Refer to FUEL TANK.
1	Air filter case cover	1
2	Intake air temperature sensor coupler	1	Disconnect.
3	Cylinder head breather hose	1
4	Air filter case	1
5	Air filter case assembly bracket	1
6	Holder	1
7	Intake air temperature sensor	1
8	Cover	1
9	Throttle cable cover	1

Removing the throttle body
Order	Job/Parts to remove	Q’ty	Remarks
10	Throttle cable	2
11	Fuel hose	1
12	Throttle body	1
13	Exhaust pipe bracket	1
14	Throttle body joint	1
15	Holder	1
16	Ignition coil bracket	1
17	Ignition coil	1
18	Air filter case bracket (right)	1
19	Air filter case bracket (left)	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:

Injector resistance

Refer to CHECKING THE INJECTOR.

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.

4.Reset:

Use the diagnostic code number “87”.

Refer to DIAGNOSTIC CODE: SENSOR OPERATION TABLE.

Yamaha diagnostic tool USB (US)

90890-03275

Yamaha diagnostic tool (A/I)

90890-03273

CHECKING THE FUEL PRESSURE

1.Check:

Fuel pressure

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

Refer to GENERAL CHASSIS.

b.Remove the fuel tank bracket 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:

Throttle position sensor

Refer to CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE.

2.Adjust:

Throttle position sensor angle

a.Connect the Yamaha diagnostic tool.

Refer to YAMAHA DIAGNOSTIC TOOL.

Yamaha diagnostic tool USB (US)

90890-03275

Yamaha diagnostic tool (A/I)

90890-03273

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)

3.Reset:

Use the diagnostic code number “87”.

Refer to DIAGNOSTIC CODE: SENSOR OPERATION TABLE.

INSTALLING THE AIR FILTER CASE ASSEMBLY BRACKET

1.Install:

Air filter case assembly bracket “1”

: Align the projections “a” on the air filter case assembly bracket with the grooves “b” in the air filter case “2”, and then push down the portion “c”.