Yamaha XMAX YP125R - Service manual > Adjusting the valve clearance

The following procedure applies to all of the valves.

TIP

• Valve clearance adjustment should be made on a cold engine, at room temperature.
• When the valve clearance is to be measured or adjusted, the piston must be at top dead center (TDC) on the compression stroke.

1. Remove:

• Storage box

2. Remove:

• V-belt case air filter cover "1"

3. Remove:

• Spark plug cap "1"
• Spark plug
• Tappet covers "2"
• Camshaft sprocket cover "3"

4. Remove:

• Timing mark accessing plug "1"

5. Measure:

• Valve clearance

Out of specification → Adjust.

Valve clearance (cold) Intake 0.08-0.12 mm (0.0031-0.0047 in) Exhaust 0.16-0.20 mm (0.0063-0.0079 in)

a. Turn the primary sheave nut on the left side of the crankshaft counterclockwise to turn the crankshaft.

b. When the piston is at TDC on the compression stroke, align the "I" mark "a" on the camshaft sprocket with the stationary pointer "b" on the cylinder head.

c. Align the "I" mark "c" on the generator rotor with the stationary pointer "d" on the generator cover.

d. Measure the valve clearance with a thickness gauge "1".

Out of specification → Adjust.

6. Adjust:

• Valve clearance

a. Loosen the locknut "1".

b. Insert a thickness gauge "2" between the end of the adjusting screw and the valve tip.

c. Turn the adjusting screw "3" in direction "a" or "b" with the tappet adjusting tool "4" until the specified valve clearance is obtained.

Direction "a" Valve clearance is increased.

Direction "b" Valve clearance is decreased.

Tappet adjusting tool 90890-01311

Six piece tappet set YM-A5970

d. Hold the adjusting screw to prevent it from moving and tighten the locknut to specification.

Locknut (valve clearance adjusting screw) 14 Nm (1.4 m*kgf, 10 ft*lbf)

e. Measure the valve clearance again.

f. If the valve clearance is still out of specification, repeat all of the valve clearance adjustment steps until the specified clearance is obtained.

7. Install:

• Timing mark accessing plug (along with the O-ring )
• Camshaft sprocket cover (along with the O-ring )
• Tappet covers (along with the O-rings )
• Spark plug
• Spark plug cap

Timing mark accessing plug 8 Nm (0.8 m*kgf, 5.8 ft*lbf)

Camshaft sprocket cover 10 Nm (1.0 m*kgf, 7.2 ft*lbf)

Tappet cover 10 Nm (1.0 m*kgf, 7.2 ft*lbf)

Spark plug 18 Nm (1.8 m*kgf, 13 ft*lbf)

8. Install:

• V-belt case air filter cover

9. Install:

• Storage box

Adjusting the exhaust gas volume

TIP

Be sure to set the CO density level to standard, and then adjust the exhaust gas volume.

1. Remove:

• Upper panel

2. Set the main switch to "OFF".

3. Disconnect:

• Self-diagnosis signal coupler

4. Connect:

• FI diagnostic tool "1"

FI diagnostic tool 90890-03182

5. While pressing the "MODE" button "1", set the main switch to "ON".

TIP

• "DIAG" appears on the LCD "2" of the FI diagnostic tool.
• "POWER" LED (Green) "3" comes on.

6. Press the "UP" button to select the CO adjustment mode "CO" or the diagnostic mode "DIAG".

7. After selecting "CO", press the "MODE" button.

8. Check that "C1" appears on the LCD of the FI diagnostic tool, and then press the "MODE" button.

9. Start the engine.

NOTICE

Perform the adjustment after the battery has been sufficiently charged.

10.Change the CO adjustment volume by pressing the "UP" and "DOWN" buttons.

TIP

The CO adjustment volume and engine idling speed appears on the LCD of the FI diagnostic tool.

• To decrease the CO adjustment volume, press the "DOWN" button.
• To increase the CO adjustment volume, press the "UP" button.

11.Release the "DOWN" and "UP" buttons to execute the selection.

12.Set the main switch to "OFF" to cancel the mode.

13.Disconnect:

• FI diagnostic tool

14.Connect:

• Self-diagnosis signal coupler

15.Install:

• Upper panel

Adjusting the throttle cable free play

1. Check:

• Throttle cable free play "a"

Out of specification → Adjust.

Throttle cable free play 3.0-5.0 mm (0.12-0.20 in)

2. Adjust:

• Throttle cable free play

a. Slide back the rubber cover "1".

b. Loosen the locknut "2".

c. Turn the adjusting nut "3" in direction "a" or "b" until the specified throttle cable free play is obtained.

Direction "a" Throttle cable free play is increased.

Direction "b" Throttle cable free play is decreased.

d. Tighten the locknut.

e. Slide the rubber cover to its original position.

WARNING

After adjusting the throttle cable free play, start the engine and turn the handlebar to the right and to the left to ensure that this does not cause the engine idling speed to change.

See also: