Yamaha XMAX YP125R - Service manual > Checking the lean angle sensor

1. Remove:

• Lean angle sensor

2. Check:

• Lean angle sensor output voltage Out of specification → Replace.

Lean angle sensor output voltage

Less than 45º: 0.4-1.4 V

More than 45º: 3.7-4.4 V

a. Connect the test harness-lean angle sensor (6P) between the lean angle sensor and wire harness.

b. Connect the pocket tester (DC 20 V) to the test harness-lean angle sensor (6P).

Test harness-lean angle sensor (6P) 90890-03209

Pocket tester 90890-03112

Analog pocket tester YU-03112-C

• Positive tester probe → yellow/green "1"
• Negative tester probe → gray/black "2"

c. Set the main switch to "ON".

d. Turn the lean angle sensor 45º.

e. Measure the lean angle sensor output voltage.

Checking the starter motor operation

1. Check:

• Starter motor operation

Does not operate → Perform the electric starting system troubleshooting, starting with step 4.

a. Connect the positive battery terminal "1" and starter motor lead "2" with a jumper lead "3".

WARNING

• A wire that is used as a jumper lead must have at least the same capacity of the battery lead, otherwise the jumper lead may burn.
• This check is likely to produce sparks, therefore, make sure no flammable gas or fluid is in the vicinity.

b. Check the starter motor operation.

Checking the stator coil

1. Disconnect:

• Stator coil coupler (from the wire harness)

2. Check:

• Stator coil resistance

Out of specification → Replace the crankshaft position sensor/stator assembly.

Stator coil resistance 0.28-0.42 Ω at 20 ºC (68 ºF) (YP125R) 0.32-0.48 Ω at 20 ºC (68 ºF) (YP250R)

a. Connect the pocket tester (Ω × 1) to the stator coil coupler as shown.

Pocket tester 90890-03112 Analog pocket tester YU-03112-C

• Positive tester probe → white "1"
• Negative tester probe → white "2"
• Positive tester probe → white "1"
• Negative tester probe → white "3"
• Positive tester probe → white "2"
• Negative tester probe → white "3"

b. Measure the stator coil resistance.

Checking the rectifier/regulator

1. Check:

• Charging voltage

Out of specification → Replace the rectifier/ regulator.

Charging voltage 14 V at 5000 r/min

a. Connect the engine tachometer to the spark plug lead.

b. Connect the pocket tester (DC 20 V) to the battery as shown.

Pocket tester 90890-03112

Analog pocket tester YU-03112-C

• Positive tester probe → positive battery terminal "1"
• Negative tester probe → negative battery terminal "2"

c. Start the engine and let it run at approximately 5000 r/min.

d. Measure the charging voltage.

Checking the horn

1. Check:

• Horn resistance

Out of specification → Replace.

Coil resistance 1.4 Ω at 20 ºC (68 ºF)

a. Disconnect the horn connectors from the horn terminals.

b. Connect the pocket tester (Ω × 1) to the horn terminals.

Pocket tester 90890-03112

Analog pocket tester YU-03112-C

• Positive tester probe → horn terminal "1"
• Negative tester probe → horn terminal "2"

c. Measure the horn resistance.

Checking the fuel sender

1. Remove:

• Fuel sender

2. Check:

• Fuel sender resistance

Out of specification → Replace the fuel sender.

Sender unit resistance (full) 20.0 Ω

Sender unit resistance (empty) 140.0 Ω

a. Connect the pocket tester (Ω × 10) to the fuel sender terminal as shown.

Pocket tester 90890-03112

Analog pocket tester YU-03112-C

• Positive tester probe → sky blue "1"
• Negative tester probe → black "2"

A. Full fuel tank position

B. Empty fuel tank position

b. Measure the fuel sender resistance.

Checking the fuel level warning light

This model is equipped with a self-diagnosis device for the fuel level detection circuit.

1. Check:

Fuel level warning light "1" (Set the main switch to "ON".) The warning light comes on for a few seconds, then goes off → The warning light is OK.

The warning light does not come on → Replace the meter assembly.

All LCD segments of the fuel meter "2" and the fuel level warning light "1" flash (open or short circuit detected in fuel sender) → Replace the fuel sender.

Checking the speed sensor

1. Check:

• Speed sensor output voltage

Out of specification → Replace.

Output voltage reading cycle 0.6 V to 4.8 V to 0.6 V to 4.8 V

a. Connect the pocket tester (DC 20 V) to the speed sensor coupler (wire harness end) as shown.

Pocket tester 90890-03112

Analog pocket tester YU-03112-C

• Positive tester probe → gray "1"
• Negative tester probe → gray/black "2"

b. Set the main switch to "ON".

c. Elevate the front wheel and slowly rotate it.

d. Measure the voltage of gray and gray/black.

With each full rotation of the front wheel, the voltage reading should cycle from 0.6 V to 4.8 V to 0.6 V to 4.8 V.

Checking the radiator fan motor

1. Check:

• Radiator fan motor

Faulty/rough movement → Replace.

a. Disconnect the radiator fan motor coupler from the wire harness.

b. Connect the battery (DC 12 V) as shown.

• Positive tester probe → red "1"
• Negative tester probe → black "2"

c. Measure the radiator fan motor movement.

See also: