2002 YAMAHA YZ250F ignition

CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM
.......................... 6-1
MAP-CONTROLLED CDI UNIT
................ 6-2
IGNITION SYSTEM
................................... 6-3
THROTTLE POSITION
SENSOR SYSTEM
.................................... 6-7
CHAPTER 7
TUNING
ENGINE
..................................................... 7-1
CHASSIS
................................................. 7-11

GEN
INFO
1 - 8
SPECIAL TOOLS
YU-33975, 90890-01403 Steering nut wrench
This tool is used when tighten the steering ring nut to
specification.YU-33975 90890-01403
YM-1423, 90890-01423 Damper rod holder
Use this tool to remove and install the damper rod.YM-1423 90890-01423
YM-01442, 90890-01442 Fork seal driver
This tool is used when install the fork oil seal.YM-01442 90890-01442
YU-3112-C, 90890-03112 Pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-3112-C 90890-03112
YU-8036-B
90890-03113Inductive tachometer
Engine tachometer
This tool is needed for observing engine rpm.YU-8036-B 90890-03113
YM-33277-A, 90890-03141 Timing light
This tool is necessary for checking ignition timing.YM-33277-A 90890-03141
YM-4019, 90890-04019 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.YM-4019 90890-04019
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
YM-4111, 90890-04111
YM-4116, 90890-04116Valve guide remover
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to remove and install the valve
guide.YM-4111
YM-411690890-04111
90890-04116
Part number Tool name/How to use Illustration

GEN
INFO
1 - 9
SPECIAL TOOLS
YM-4112, 90890-04112
YM-4117, 90890-04117Valve guide installer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to install the valve guide.YM-4112
YM-411790890-04112
90890-04117
YM-4113, 90890-04113
YM-4118, 90890-04118Valve guide reamer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
This tool is needed to rebore the new valve guide.YM-4113
YM-411890890-04113
90890-04118
YM-34487
90890-06754Dynamic spark tester
Ignition checker
This instrument is necessary for checking the ignition
system components.YM-34487 90890-06754
ACC-QUICK-GS-KT
90890-85505Quick gasket

YAMAHA Bond No. 1215
This sealant (Bond) is used for crankcase mating
surface, etc.ACC-QUICK-GS-KT 90890-85505
Part number Tool name/How to use Illustration

SPEC

2 - 3
GENERAL SPECIFICATIONS
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto

SPEC
2 - 16
MAINTENANCE SPECIFICATIONS
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Advancer type Electrical ----
CDI:
Magneto-model (stator)/manufac-
turer5SF-00/YAMAHA ----
Charging coil 1 resistance (color) 720 ~ 1,080 Ω at 20 ˚C (68 ˚F)
(Green – Brown)----
Charging coil 2 resistance (color) 44 ~ 66 Ω at 20 ˚C (68 ˚F)
(Black – Pink)----
Pickup coil resistance (color) 248 ~ 372 Ω at 20 ˚C (68 ˚F)
(White – Red)----
CDI unit-model/manufacturer 5SG-00/YAMAHA ----
Ignition coil:
Model/manufacturer 4SR-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary coil resistance 0.20 ~ 0.30 Ω at 20 ˚C (68 ˚F) ----
Secondary coil resistance 9.5 ~ 14.3 kΩ at 20 ˚C (68 ˚F) ----
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Stator M6 × 1.0 3 10 1.0 7.2
Rotor M10 × 1.25 1 48 4.8 35
Neutral switch M5 × 0.8 2 4 0.4 2.9
Ignition coil M6 × 1.0 2 7 0.7 5.1

2 - 18
SPEC

CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1
Hose guide
2
Brake hose
3
Fuel tank breather hose
4
Engine stop switch lead
5
Oil tank breather hose
6
Sub-wire harness
7
Neutral switch lead
8
Cable guide
9
Cylinder head breather hose
0
CDI magneto lead
A
Radiator breather hose
B
Carburetor breather hose
C
Carburetor overflow hose
D
Ignition coil lead
E
CDI unit lead
Å
Pass the fuel tank breather hose
between the handlebar and ten-
sion bar, then insert its end into
the hole of the number plate.
ı
Fasten the engine stop switch
lead and ignition coil lead of the
sub-wire harness.
Ç
Fasten the sub-wire harness
and engine stop switch lead.
Fasten the engine stop switch
lead at its protecting tube.
Î
Fasten the sub-wire harness.
‰
Pass the sub-wire harness
between the upper engine
brackets.
Ï
Fasten the sub-wire harness at
its white tape.
Ì
Fasten the sub-wire harness.
Ó
Make sure that the throttle posi-
tion sensor lead coupler does
not go out side the chassis.
È
Fasten the throttle position sen-
sor lead.
Ô
Pass the carburetor breather
hose and overflow hose
between the connecting rod and
cross tube (frame).

Fasten the neutral switch lead
on the oil hose with a plastic
locking tie and cut off the tie
end.
Ò
Pass the clutch cable through
the cable guide.
˜
Pass the cylinder head breather
hose through the hose guide.
ˆ
Fasten the neutral switch lead.

2 - 19
SPEC

CABLE ROUTING DIAGRAM
Ø
Fasten the neutral switch lead
and CDI magneto lead.
∏
Pass the clutch cable on the
inside the cylinder head
breather hose.
Œ
Pass the clutch cable in front of
the radiator mounting boss.
Â
Fit the brake hose into the
guides on the protector.
Í
Pass the carburetor breather
hoses and overflow hose so
that all there hoses do not con-
tact the rear shock absorber.
Ê
Pass the neutral switch lead
and CDI magneto lead through
the cable guide.
Ë
Fasten the ground lead
together with the ignition coil.
√
Pass the clutch cable through
the cable guides.
„
Position each lead at the lower
left of the main tube (frame).

2 - 20
SPEC

1
Spark plug lead
2
Ignition coil
3
CDI unit
4
CDI unit band
5
Throttle cable (return)
6
Throttle cable (pull)
7
Cable guide
8
CDI unit lead
9
CDI unit stay
0
Radiator breather hose
A
Radiator hose 4
Å
Pass the CDI unit lead
between the radiator hose and
radiator mounting boss.
ı
Pass the throttle cables
through the cable guide.
Ç
Pass the throttle cables and
CDI unit lead through the cable
guide.
Î
Pass the throttle cables under
the radiator mounting boss.
‰
Insert the CDI unit band over
the CDI unit stay (frame) as far
as possible.
Ï
Pass the radiator breather
hose in front of the radiator
mounting rear boss and at the
left of the chassis. And then,
pass it between the radiator
hose 4 and down tube (frame)
and between the engine and
lower engine guard.
CABLE ROUTING DIAGRAM