2010 YAMAHA YZ250F charging

2-10
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque ti ghtening after break-in or before each race.
Item StandardLimit
Ignition system: Advancer type Electrical----
CDI: Magneto-model (stator)/manufacturer 17D-50/YAMAHA----
Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F)
(Green–Brown) ----
Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Black–Pink) ----
Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White–Red) ----
CDI unit-model/manufacturer 17D-50/YAMAHA (For USA and CDN) ----
17D-60/YAMAHA (Except for USA and
CDN) ----
Ignition coil: Model/manufacturer 5UL-20/DENSO----
Minimum spark gap 6 mm (0.24 in)----
Primary coil resistance 0.08–0.10 Ωat 20 °C (68 °F) ----
Secondary coil resistance 4.6–6.8 kΩat 20 °C (68 °F) ----
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Spark plug M10S × 1.0 1 13 1.3 9.4
Camshaft cap M6 × 1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12 × 1.0 1 28 2.8 20
Cylinder head (stud bolt) M6 × 1.0 2 7 0.7 5.1
Cylinder head (stud bolt) M8 × 1.25 1 15 1.5 11
Cylinder head (bolt) M9 × 1.25 4 38 3.8 27
Cylinder head (nut) M6 × 1.0 2 10 1.0 7.2
Cylinder head cover M6 × 1.0 2 10 1.0 7.2
Cylinder M6 × 1.0 1 10 1.0 7.2
Balancer weight M6 × 1.0 2 10 1.0 7.2
Balancer shaft driven gear M14 × 1.0 1 50 5.0 36
Timing chain guide (intake side) M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 7 0.7 5.1
Impeller M8 × 1.25 1 14 1.4 10
Radiator hose clamp M6 × 1.0 10 2 0.2 1.4
Coolant drain bolt M6 × 1.0 1 10 1.0 7.2
Water pump housing M6 × 1.0 4 10 1.0 7.2
Radiator M6 × 1.0 6 10 1.0 7.2
Radiator pipe M6 × 1.0 1 10 1.0 7.2
Oil pump cover M4 × 0.7 1 1.7 0.17 1.2
Oil pump M6 × 1.0 3 10 1.0 7.2

6-3
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap test Spark→ *Clean or replace spark plug.
No spark ↓
Check entire ignition system for connection.
(couplers, leads and ignition coil) No good
→
Repair or replace.
OK ↓
Check engine stop switch. No good→Replace.
OK ↓
Check ignition coil. (primary coil and secondary
coil) No good
→
Replace.
OK ↓
Check CDI magneto. (pickup coil and charging
coil) No good
→
Replace.
OK ↓
Check neutral switch. No good→Repair or replace.
OK ↓
Replace CDI unit.
Dynamic spark tester: YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/90890-03112

6-5
IGNITION SYSTEM
2. Inspect:• Charging coil 1 resistanceOut of specification →Replace.
3. Inspect: • Charging coil 2 resistanceOut of specification →Replace. CHECKING THE NEUTRAL
SWITCH
1. Inspect:
• Neutral switch conduction
Not conductive while it is in neutral →
Replace.
Conductive while it is engaged →Re-
place.
Set the tester selection position to " Ω
× 1".
CHECKING THE CDI UNIT
Check all electrical components. If no
fault is found, replace the CDI unit.
Then check the electrical compo-
nents again.
Tester (+) lead
→Brown lead "1"
Tester (-) lead →Green lead "2"
Charging
coil 1 resis- tance Tester se-
lector posi- tion
720-1,080
Ω at 20 °C
(68 °F) Ω
×100
Tester (+) lead →Pink lead "1"
Tester (-) lead →Black lead "2"
Charging
coil 2 resis- tance Tester se-
lector posi- tion
44-66 Ω at
20 °C (68 °F) Ω ×10
B
WBr
G P
R
B
WBr
GP
R
Tester (+) lead →Sky blue lead "1"
Tester (-) lead →Ground "2"
Result Conductive (while gear
is in neutral)

6-6
THROTTLE POSITION SENSOR SYSTEM
THROTTLE POSITION SENSOR SYSTEM
INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.
*marked: Refer to "IGN ITION SYSTEM" section.
Use the following special tools in this inspection.
Check entire ignition system for connection. No good →Repair or replace.
OK ↓
Check throttle position sensor. (Throttle position
sensor coil) No good
→
Replace.
OK ↓
*Check CDI magneto. (Charging coil) No good→Replace.
OK ↓
Check CDI unit. (Throttle position sensor input
voltage) No good
→
Replace.
Pocket tester:
YU-3112-C/90890-03112