YAMAHA TT600RE 2004 Service Manual

ENGINSPECTION AND REPAIR
5-27
•Apply Prussian blue (Dykem) to the valve seal
surface.
•Install the valve in the cylinder head.
•Press the valve onto the housing through the
guide to leave a clear outline.
•Measure the valve seat width once more. If
the width of the valve is out of specification
alter and relap.

VALVE SPRINGS
1. Measure:
•Free width of valve springs (a)
Out of specification ➔Replace.
Free width of valve springs
(intake and exhaust):
Internal spring External spring 40.1 mm 43.8 mm
Valve spring load:
Internal spring (intake and exhaust) 164.8 ~ 190.2 N
(16.80 ~ 19.39 kgf) at 22.7 mm
External spring (intake) 71.6 ~ 87.3 N
(7.3 ~ 8.9 kgf) at 34.2 mm
External spring (exhaust) 149.1 ~ 182.4 N
(15.2 ~ 18.6 kgf) at 34.2 mm
2. Measure:
•Spring load
Out of specification ➔Replace.
(b) Length of loaded spring
3. Measure:
•Inclination of spring (a)
Out of specification ➔Replace.
Spring inclination limit:
Internal spring External spring 2.5°/1.7 mm 2.5°/1.9 mm
ProCarManuals.com

INSPECTION AND REPAIR
5-28
ENG
CAMSHAFT
1. Inspect:
•Cam eccentrics
Pitting/Scratches/Blue colour ➔Replace
camshaft.
2. Measure:
•Cam eccentrics
Out of specification ➔Replace camshaft.
(a) (b)
Intake: 36.47~36.57 mm 30.06~30.16 mm
Exhaust: 36.62~36.72 mm 30.11~30.21 mm
ROCKER ARMS AND ROCKER SHAFT
1. Inspect:
•Rocker shafts
Blue colour/Grooves ➔Replace shafts
and check lubrication system.
2. Inspect:
•Rocker shaft slot (1)
•Surface in contact with cam eccentric (2)
•Adjuster surface (3)
Pitting/Wear/Scratches/Blue colour ➔
Replace and check lubrication system.
ProCarManuals.com

ENGINSPECTION AND REPAIR
5-29
3. Measure:
•Rocker arm-shaft clearance
Rocker arm-shaft clearance
Internal diameter (a) of rocker arm –
External diameter (b) of shaft
Out of specification ➔Replace whole
unit.
Rocker shaft clearance: 0.009 ~ 0.042 mm
CAMSHAFT CHAIN AND SPROCKET
1. Inspect:
•Chain
Stiffness/Cracks ➔Replace timing chain
and sprocket.
2. Inspect:
•Sprocket
Wear/Damage ➔Replace timing chain
and sprocket.
(1) 1/4 tooth (maximum)
(2) New sprocket tooth profile
(3) Roller
(4) Sprocket
ProCarManuals.com

INSPECTION AND REPAIR
5-30
ENG
CAMSHAFT CHAIN GUIDE
1. Inspect:
•Side chain guide (exhaust) (1)
•Side chain guide (intake) (2)
Wear/Damage ➔Replace.
CYLINDER AND PISTON
1. Inspect:
•Piston and cylinder walls
Vertical scratches ➔Replace cylinder
liner and piston.
2. Measure:
•Piston-cylinder clearance
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
Measurement steps:
•Measure cylinder bore “C” with a cylinder
gauge.
(1) 50 mm from top of cylinder
NOTE:
Measure bore parallel and at right angles to the
driving shaft. Then calculate average measure-
ment. First step
Standard
Wear limit
Cylinder 94.97 ~ 95.02 mm 95.1 mm
bore “C”
C = X + Y
2
•If the measurements are out of tolerance,
replace the cylinder liner, piston and circlips
all together.
•Measure diameter “P” of the piston skirt with a
micrometer.
(1) 5 mm from the lower edge of the piston Second step
Piston “P” size:
Standard 94.915 ~ 94.965 mm
X
Y
C
ProCarManuals.com

ENGINSPECTION AND REPAIR
5-31
•If the measurements are out of tolerance,
replace the piston and circlips all together.
•Calculate the piston-cylinder free play accord-
ing to the following formula.
Third step
Piston-cylinder clearance =
Cylinder boring “C” –
Piston skirt diameter “P”
Piston-cylinder clearance: 0.045 ~ 0.065 mm
: 0.15 mm
•If the measurements are out of tolerance,
replace the cylinder liner, piston and circlips
all together.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
ProCarManuals.com

INSPECTION AND REPAIR
5-32
ENG
PISTON RINGS
1. Measure:
•Side clearance of rings
Use a thickness gauge.
Out of specification ➔Replace piston.
NOTE:
Before measuring side clearance, remove carbon
deposits from the piston ring seats and from the
rings themselves.
Piston ring side clearance
(installed):
Upper ring 0.04 ~ 0.08 mm
Lower ring 0.03 ~ 0.07 mm
: 0.13 mm
Oil scraper 0.02 ~ 0.06 mm
Piston ring end gap
(fitted into cylinder):
Upper ring 0.30 ~ 0.45 mm
: 0.7 mm
Lower ring 0.30 ~ 0.45 mm
: 0.8 mm
Oil scraper (tracks) 0.20 ~ 0.70 mm
2. Install:
•Ring (into the cylinder)
NOTE:
Fit each ring into the cylinder and push it to about
20 mm from the top edge of the cylinder. Push the
ring into the cylinder with the piston so that it is
perfectly perpendicular to the cylinder axis.
(a) 20 mm
3. Measure:
•Ring end gap Out of specification ➔Replace.
NOTE:
It is impossible to measure the oil scraper end
gap. If the oil scraper port appears too large,
replace all three rings.
ProCarManuals.com

ENGINSPECTION AND REPAIR
5-33
PISTON PIN
1. Check:
•Piston pin
Blue colour/Grooves ➔Replace and
check lubrication system.
External diameter (pin): 21.991 ~ 22.000 mm
Clearance between piston pin and pin
seat on piston: 0.004 ~ 0.024 mm
: 0.07 mm
2. Measure:
•External diameter (a) of pin
Out of specification ➔Replace.
3. Measure:
•Clearance between piston pin and pin
seat
Out of specification ➔Replace.
Clearance between piston pin and
piston = Diameter of pin seat on piston (b) –
Diameter of pin (a)
CLUTCH
1. Inspect:
•Clutch gear assy teeth
Cracks/Pitting (on edges):
Moderate ➔Burr.
Accentuated ➔Replace clutch gear assy.
NOTE:
Pitting of the gear assy teeth causes irregular
functioning.
ProCarManuals.com

INSPECTION AND REPAIR
5-34
ENG
2. Inspect:
•Clutch gear assy bearing
Damaged ➔Replace.
3. Inspect:
•Groove in clutch boss.
Pitting:
Moderate ➔Burr.
Accentuated ➔ Replace clutch boss.
NOTE:
Pitting of the clutch boss grooves causes irregular
functioning.
4. Measure:
•Thickness of friction plates
Out of specification ➔Replace all plates.
Thickness Wear
limit
Type “A” 2.94 ~ 3.06 mm 2.8 mm
(2 parts)
Type “B” 2.72 ~ 2.88 mm 2.6 mm
(6 parts)
5. Measure:
•Deformation of clutch plates
Out of specification ➔Replace all plates.
Clutch plates deformation: : 0.2 mm
Clutch push rod runout:: 0.2 mm
6. Measure:
•Runout limit of clutch push rod.
Turn clutch push rod on two V blocks.
ProCarManuals.com

ENGINSPECTION AND REPAIR
5-35
7. Measure:
•Free length of clutch compression springs
(a)
Out of specification ➔Replace all springs.
OIL PUMP
1. Measure:
•Clearance between rotors (a)
(Between the internal rotor (1) and the
external rotor (2))
•Side clearance (b)
(Between the external rotor (2) and the
pump stator (3))
Out of specification ➔Replace oil pump.
Free length of clutch compression
spring (a): 42.8 mm
Oil pump clearances:
Clearance between 0.12 mm
rotors (a) : 0.2 mm
Side clearance (b) 0.03 ~ 0.08 mm
: 0.15 mm
2. Inspect:
•Oil pump drive gear (1)
•Oil pump driven gear (2)
Wear/Cracks/Damage ➔Replace.
PRIMARY TRANSMISSION
1. Inspect:
•Primary drive gear teeth (1)
•Primary driven gear teeth (2)
Wear/Damage ➔Replace both gears.
Excess noise during functioning ➔
Replace both gears.
ProCarManuals.com

INSPECTION AND REPAIR
5-36
ENG
TRANSMISSION AND GEARBOX
1. Inspect:
•Shift fork pin (1)
•Shift fork pawl (2)
Lines/Creases/Wear ➔Replace.
2. Inspect:
•Shift cam groove
•Shift cam pins
Wear/Damage ➔Replace.
3. Check:
•Shift fork movement
Rough functioning ➔Replace shift forks
and/or guide bars.
4. Inspect:
•Guide bar
Turn on a flat surface.
Curvature ➔Replace.
WARNING
Do not attempt to straighten the deformed
guide bar.
5. Measure:
•Transmission shaft eccentricity.
Use the centring tool and micrometer.
Out of specification ➔Replace bent shaft.
Transmission shaft eccentricity: : 0.08 mm
ProCarManuals.com