Page 654 of 786

5 - 64
CHAS
EC586000
HANDLING NOTE
WARNING
This shock absorber is provided with a
separate type tank filled with high-pressure
nitrogen gas. To prevent the danger of
explosion, read and understand the follow-
ing information before handling the shock
absorber.
The manufacturer can not be held respon-
sible for property damage or personal
injury that may result from improper han-
dling.
1. Never tamper or attempt to disassemble
the cylinder or the tank.
2. Never throw the shock absorber into an
open flame or other high heat. The
shock absorber may explode as a result
of nitrogen gas expansion and/or dam-
age to the hose.
3. Be careful not to damage any part of the
gas tank. A damaged gas tank will impair
the damping performance or cause a
malfunction.
4. Take care not to scratch the contact sur-
face of the piston rod with the cylinder;
or oil could leak out.
5. Never attempt to remove the plug at the
bottom of the nitrogen gas tank. It is
very dangerous to remove the plug.
6. When scrapping the shock absorber, fol-
low the instructions on disposal.
EC587000
NOTES ON DISPOSAL (YAMAHA DEALERS
ONLY)
Before disposing the shock absorber, be sure
to extract the nitrogen gas from valve 1. Wear
eye protection to prevent eye damage from
escaping gas and/or metal chips.
WARNING
To dispose of a damaged or worn-out
shock absorber, take the unit to your
Yamaha dealer for this disposal procedure.
REAR SHOCK ABSORBER
Page 656 of 786
5 - 65
CHAS
EC583000
REMOVAL POINTS
EC583320
Bearing
1. Remove:
•Stopper ring (upper bearing) 1
NOTE:
Press in the bearing while pressing its outer
race and remove the stopper ring.
2. Remove:
•Upper bearing 1
NOTE:
Remove the bearing by pressing its outer race.
3. Remove:
•Lower bearing 1
NOTE:
Remove the bearing by pressing its outer race.
EC584000
INSPECTION
Rear shock absorber
1. Inspect:
•Damper rod 1
Bends/damage → Replace absorber
assembly.
•Shock absorber 2
Oil leaks → Replace absorber assembly.
Gas leaks → Replace absorber assem-
bly.
•Spring 3
Damage → Replace spring.
Fatigue → Replace spring.
Move spring up and down.
•Spring guide 4
Wear/damage → Replace spring guide.
•Bearing 5
Free play exists/unsmooth revolution/rust
→ Replace.
REAR SHOCK ABSORBER
Page 666 of 786

6 - 1
–+ELECELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1Headlight
2Multi-function display
3“ENGINE STOP” but-
ton
4Clutch switch
5Diode
6Starter relay diode
7TPS (throttle posi-
tion sensor)
8Starter relay
9Fuse
0Starting circuit cut-off
relayATaillight
BNeutral switch
CStarter motor
DAC magneto
ERectifier/regulator
FIgnition coil
GSpark plug
HStart switch
IMain switch
JCDI unit
KSpeed sensor
LBatteryCOLOR CODE
B ...................... Black
Br ..................... Brown
Ch .................... Chocolate
Dg .................... Dark green
Gy .................... Gray
L....................... Blue
O ...................... Orange
R ...................... Red
Sb .................... Sky blue
W ..................... White
EC612000
WIRING DIAGRAM
FGH
I
J
K
L
1 234
56
789
0A
B C
D E
B/L
W
W
R
BR/BBr
R
BR/BBr
R
Y
Y
L/R/BBB
SbL/W
L/YBBB
WY
RY
R
LY
B
YLB/L
B
B
ON
OFF
10A
BB
OFF
START
R-BrL/W
B
BrL/W
BrL/W
L/B
-Y
Y
B
LY
B
L/WSb
B/WBBB
W/R/W
R/
BGyBrL/W
ON
STOP
O
LSbB/L
W RBrB/W
L
/
BGyWR
/B
B O
L/YSbL/R
R W
Y W
Y W
Y
L B
B
B
RRR/B
B Br B
B B B B
L/W
R
R
R R B
R
BrBr
L/W L/
W
Br B
L/B
L/B
L/R
Br
R/B
L/B L
/W
B/W
WW
/RW
RO
L
Y
ELO
B
L
Y
B/LSb*1
Sb
*2B/W
B
B
L/R L/Y L/Y
B
SbSbL/W
B
Gy
SbBB/LYO
L
*2
O B
L YL/W
B/L
*1
D
E
CI
6
H4 5
B3J
K
2FG
7
8L9
1A
*2
*1
W
B
R/W
Ch
Dg
Y
B BrRW
WRB/W
SIGNAL
+
Backup
SLCT1
SLCT2
RST
GND
BrR/WB
B
R/WBr
WRB/W
R B
W
ChDgYB
B/WWRB/WWR
0
R
W
W W
L/WB/L
Y B
RB
B
L
L
*1: For USA
*2: Except for USA
Y ...................... Yellow
B/L ................... Black/Blue
B/W .................. Black/White
L/B ................... Blue/Black
L/R ................... Blue/Red
L/Y ................... Blue/Yellow
L/W .................. Blue/White
R/B................... Red/Black
R/W.................. Red/White
Page 668 of 786

–+ELEC
6 - 2
MAP-CONTROLLED CDI UNIT
MAP-CONTROLLED CDI UNIT
A map-controlled, CDI ignition system is used in the WR450F.
The microcomputer in the CDI unit detects the engine speed and throttle position, thus determining
the optimum ignition timing through the entire operating range. In this way, quick throttle response
can be achieved according to various riding conditions.
Throttle position sensorCDI unitIgnition coil
Pickup coilAC magneto rotor
Function of Component
Component Function
TPS
(throttle position sensor)Detects throttle valve opening and inputs it into the computer in the
CDI unit as a throttle opening signal.
Pickup coil Detects signal rotor revolutions and inputs them into the computer in
the CDI unit as engine revolution signals.
CDI unit The signals of the TPS and pickup coil sensor are analyzed by the
computer in the CDI unit, which then adjusts ignition timing for the
operation requirements.
Principal of 3-Dimensional Control
Conventionally, ignition timing was controlled only
by engine revolutions (2-dimensional control).
However, ignition timing needs advancement also
by engine load. Thus, accurate ignition timing can
be determined by adding throttle opening to deter-
mine ignition timing (3-dimensional control).
3-D Image Map of Ignition Timing
(different from actual characteristics)
Ignition timing
Th
rot
t
le
o
peni
ngRev
o
lut
io
ns
Page 672 of 786

–+ELEC
6 - 3
IGNITION SYSTEM
EC620000
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.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
*3 marked: Only when the ignition checker is used.
NOTE:
•Remove the following parts before inspection.
1) Seat
2) Fuel tank
•Use the following special tools in this inspection.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754Pocket tester:
YU-3112-C/90890-03112
*1 Check fuse.Replace fuse and
check wire harness.
*2 Check battery Recharge or replace.
Spark gap test*3 Clean or replace
spark plug.
Check entire ignition
system for connection.
(couplers, leads and
ignition coil)Repair or replace.
Check “ENGINE STOP”
button.Replace.
Check main switch. Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check AC magneto. Pick-up coil Replace.
Check neutral switch. Repair or replace.
Replace CDI unit.
OK
OK
No spark
OK
OK
OK
OK
OK
OK
Spark No good
No good
No good
No good
No good No good
No good
No good
No good
Page 676 of 786

6 - 4
–+ELECIGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the ignition coil from spark
plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark tester 1 (igni-
tion checker 2) as shown.
•Ignition coil 3
•Spark plug 4
ÈFor USA and CDN
ÉExcept for USA and CDN
4. Kick the kickstarter.
5. Check the ignition spark gap.
6. Start engine, and increase spark gap until
misfire occurs. (for USA and CDN only)
Minimum spark gap:
6.0 mm (0.24 in)
È
É
COUPLERS, LEADS AND IGNITION COIL
CONNECTION INSPECTION
1. Check:
•Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
•Ignition coil and spark plug as they are fit-
ted
Push in the ignition coil until it closely
contacts the spark plug hole in the cylin-
der head cover.
EC625001
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:
•“ENGINE STOP” button conduct
No continuity while being pushed → Replace.
Continuity while being freed → Replace.
2. Inspect:
•Rubber part
a
Tears/damage → Replace. Tester (+) lead
→ Black lead
1
Tester (–) lead
→ Black lead
2
B
1 B
2 Tester selec-
tor position
PUSH IN
Ω
×
×× × 1
FREE
a
Page 678 of 786
6 - 5
–+ELECIGNITION SYSTEM
MAIN SWITCH INSPECTION
1. Inspect:
•Main switch conduct
Continuous while the main switch is moved to
“OFF” → Replace.
Not continuous while the main switch is moved
to “ON” → Replace.
2. Inspect:
•Main switch indicator light
Use 12 V battery.
Indicator light does not come on → Replace.
3. Inspect:
•Rubber part a
Tears/damage → Replace. Tester (+) lead
→ Red lead
1
Tester (–) lead
→ Brown lead
2
R
1 Br
2 Tester selec-
tor position
ON
Ω
×
×× × 1
OFF
Battery (+) lead
→ Red/Black lead
1
Battery (–) lead
→ Black lead
2
a
EC626002
IGNITION COIL INSPECTION
1. Remove the ignition coil cap.
2. Inspect:
•Primary coil resistance
Out of specification → Replace.
Tester (+) lead
→ Orange lead
1
Tester (–) lead
→ Black lead
2
Primary coil
resistanceTester selector
position
0.08 ~ 0.10
Ω at
20 °C (68 °F)Ω
× 1
Page 680 of 786

6 - 6
–+ELECIGNITION SYSTEM
3. Inspect:
•Secondary coil resistance
Out of specification → Replace.
4. Inspect:
•Sealed portion of ignition coil a
•Spark plug terminal pin b
•Threaded portion of spark plug c
Wear → Replace.
AC MAGNETO INSPECTION
1. Inspect:
•Pick-up coil resistance
Out of specification → Replace.
NEUTRAL SWITCH INSPECTION
1. Inspect:
•Neutral switch conduct
No continuity while in neutral → Replace.
Continuity while in gear → Replace.
EC628000
CDI UNIT INSPECTION
Check all electrical components. If no fault is
found, replace the CDI unit. Then check the
electrical components again.Tester (+) lead
→ Orange lead
1
Tester (–) lead
→ Spark plug terminal
2
Secondary coil
resistanceTester selector
position
4.6 ~ 6.8 k
Ω at
20 °C (68 °F)k
Ω
× 1
Tester (+) lead
→ Red lead
1
Tester (–) lead
→ White lead
2
Pick-up coil
resistanceTester selector
position
248 ~ 372
Ω at
20 °C (68 °F)Ω
× 100
Tester (+) lead
→ Sky blue lead
1
Tester (–) lead
→ Ground
2
Sb
1 Ground 2
Tester selec-
tor position
NEUTRAL
Ω
×
×× × 1
IN GEAR
RW
12
–+ Ω×1
1
2L/W Sb