2004 YAMAHA TTR90 heating

CHAPTER 4
ENGINE
CARBURETOR
......................................... 4-1
CYLINDER HEAD
..................................... 4-8
CAMSHAFT AND ROCKER ARMS
....... 4-13
VALVES AND VALVE SPRINGS
........... 4-16
CYLINDER AND PISTON
....................... 4-21
CLUTCH
.................................................. 4-27
KICK AXLE
............................................. 4-33
SHIFT SHAFT
......................................... 4-34
OIL PUMP
............................................... 4-36
CDI MAGNETO (TT-R90)
....................... 4-39
CDI MAGNETO AND STARTER
CLUTCH (TT-R90E)
................................ 4-41
CRANKCASE AND CRANKSHAFT
....... 4-45
SHIFT FORK, SHIFT CAM
AND TRANSMISSION
............................ 4-48
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
...... 5-1
FRONT FORK
........................................... 5-6
HANDLEBAR
............................................ 5-9
STEERING
.............................................. 5-11
SWINGARM
............................................ 5-12
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM
.......................... 6-1
IGNITION SYSTEM
................................... 6-3
ELECTRIC STARTING SYSTEM
(TT-R90E)
.................................................. 6-7
CHARGING SYSTEM (TT-R90E)
........... 6-15
CARBURETOR HEATING SYSTEM
...... 6-17
MAINTENANCE RECORD
..................... 6-21

2 - 18
SPEC

CABLE ROUTING DIAGRAM
TT-R90
1
Crankcase breather hose
2
Wire harness
3
CDI magneto lead
4
Starter cable
5
Carburetor heating lead
6
Engine stop switch lead
7
Thermo switch
8
Thermo switch lead
9
Spark plug lead
0
Throttle cable
A
Cable holder
B
Fuel tank breather hose
C
Brake cable
Å
After fastening the starter cable, CDI magneto lead, wire harness and
thermo switch lead, cut off any excess from the plastic locking tie end.
ı
Pass the ignition coil lead through the lead guide.
Ç
Fasten the engine stop switch lead with the plastic bands.
Î
Pass the brake cable through the cable guides.
12345
9
0
B A
6
C 1Å
ı
Ç
Î
Î
A
A
67
8
20 ~ 30 mm
(0.79 ~ 1.18 in)

CABLE ROUTING DIAGRAM

3 - 23
INSP
ADJ
BATTERY INSPECTION AND CHARGING (TT-R90E)
ÅRelationship between the open-circuit voltage
and the charging time at 20 ˚C (68 ˚F)
(These values vary with the temperature, the
condition of the battery plates, and the electro-
lyte level.)
ıOpen-circuit voltage
ÇCharging time (hours)
ÎTime (minutes)
‰Charging condition of the battery
ÏAmbient temperature 20 ˚C (68 ˚F)
aCharging
bCheck the open-circuit voltage.
Check the charge of the battery, as shown
in the charts and the following example.
Example:
Open-circuit voltage = 12.0 V
Charging time = 6.5 hours
Charge of the battery = 20 ~ 30% Å
5. Charge:
Battery
(refer to the appropriate charging
method illustration)
WARNING
Do not quick charge a battery.
CAUTION:
Never remove the MF battery sealing
caps.
Do not use a high-rate battery charger
since it forces a high-amperage current
into the battery quickly and can cause
battery overheating and battery plate
damage.
If it is impossible to regulate the charging
current on the battery charger, be careful
not to overcharge the battery.
When charging a battery, be sure to
remove it from the machine. (If charging
has to be done with the battery mounted
on the machine, disconnect the negative
battery lead from the battery terminal.)
To reduce the chance of sparks, do not
plug in the battery charger until the bat-
tery charger leads are connected to the
battery.

–+ELEC
6 - 17
CARBURETOR HEATING SYSTEM
CARBURETOR HEATING SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning carburetor heating system.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Fuel tank
Use the following special tools in this inspection.
Check entire carburetor
heating system for connec-
tion.Repair or replace.
Check thermo switch. Replace.
Check carburetor heater. Replace.
Check CDI magneto. Lighting coil Replace.
Replace rectifier/regulator.
Pocket tester:
YU-3112-C/90890-03112
OK
OK
OK
No good
No good
No good
No good
OK

6 - 18
–+ELECCARBURETOR HEATING SYSTEM
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
THERMO SWITCH INSPECTION
1. Inspect:
Thermo switch operation
Faulty operation → Replace.
Inspection steps:
Remove the thermo switch.
Connect the pocket tester to the thermo
switch coupler as shown.
Tester (+) lead → Black 1
Tester (–) lead → Black 2
Immerse the thermo switch in a container
filled with water 3.
Place a thermometer 4 in the water.
Slowly heat the water, and then let it cool to
the specified temperature as indicated in
the table.
Check the thermo switch for continuity at
the temperatures indicated in the table.
ÅTT-R90
ıTT-R90E
Å
ı

6 - 19
–+ELEC
ÇThe thermo switch circuit is open.
ÎThe thermo switch circuit is closed.
Test step Water temperature Continuity
1TT-R90:
Less than 23 ± 3 ˚C
(73.4 ± 5.4 ˚F)
TT-R90E:
Less than 16 ± 3 ˚C
(60.8 ± 5.4 ˚F)YES
2TT-R90:
More than 23 ± 3 ˚C
(73.4 ± 5.4 ˚F)
TT-R90E:
More than 16 ± 3 ˚C
(60.8 ± 5.4 ˚F)NO
3TT-R90:
More than 12 ± 4 ˚C
(53.6 ± 7.2 ˚F)
TT-R90E:
More than 11 ± 3 ˚C
(51.8 ± 5.4 ˚F)NO
4TT-R90:
Less than 12 ± 4 ˚C
(53.6 ± 7.2 ˚F)
TT-R90E:
Less than 11 ± 3 ˚C
(51.8 ± 5.4 ˚F)YES
Test steps 1 & 2: Heating phase
Test steps 3 & 4: Cooling phase
WARNING
Handle the thermo switch with special
care.
Never subject the thermo switch to
strong shocks. If the thermo switch is
dropped, replace it.
Check the thermo switch operation.
Å
ı
CARBURETOR HEATING SYSTEM

6 - 20
–+ELECCARBURETOR HEATING SYSTEM
CARBURETOR HEATER INSPECTION
1. Inspect:
Carburetor heater resistance
Out of specification → Replace.
Tester (+) probe →
Carburetor heater terminal 1
Tester (–) probe →
Carburetor heater body 2
Carburetor
heater resistanceTester selector
position
6 ~ 10 Ω at
20 ˚C (68 ˚F)Ω × 1
CDI MAGNETO INSPECTION
1. Inspect:
Lighting coil resistance
Out of specification → Replace.
ÅTT-R90
ıTT-R90E
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
Lighting coil
resistanceTester selector
position
TT-R90:
0.28 ~ 0.42 Ω at
20 ˚C (68 ˚F)
TT-R90E:
0.52 ~ 0.78 Ω at
20 ˚C (68 ˚F)Ω × 1
W
Y
B
WSb
YB
1
2
1
2
Å
ı