2001 YAMAHA TTR90 Owners Manual

Page 193 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 23
ENG
 
CYLINDRE ET PISTON  
ZYLINDER UND KOLBEN 
Zylinderbohrung “C”47,000–47,005 mm
Konizität “T” 0,05 mm
Unrundheit “R” 0,05 mm
“C” = Max. D
“T” = (Max. D 
1 
 oder D

Page 194 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 24
ENG
 
CYLINDER AND PISTON 
Piston ring 
1. Measure: 
l 
Ring side clearance
Use a feeler gauge. 
Out of specification   
®  
 Replace the pis-
ton and rings as a set.
NOTE:
 
Clean carbon fr

Page 195 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 24
ENG
 
CYLINDRE ET PISTON 
ZYLINDER UND KOLBEN 
Kolbenring 
1. Messen: 
l 
Ringnutspiel
Fühlerlehre verwenden. 
Unvorschriftsmäßig  
®  
 Kolben (kom-
plett) mit Kolbenringen erneuern.
HIN

Page 196 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 25
ENG
 
CYLINDER AND PISTON 
Piston pin 
1. Inspect: 
l 
Piston pin
Blue discoloration/grooves  
®  
 
Replace, then inspect the lubrication
system.
2. Measure: 
l 
Piston pin outside diameter

Page 197 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 25
ENG
 
CYLINDRE ET PISTON 
ZYLINDER UND KOLBEN 
Kolbenbolzen 
1. Kontrollieren: 
l 
Kolbenbolzen
Blaufärbung/Riefen  
® 
 Erneuern und
Schmiersystem überprüfen.
2. Messen: 
l 
Kolbenstift-

Page 198 of 288

YAMAHA TTR90 2001  Owners Manual  
4 - 26
ENG
 
CYLINDER AND PISTON 
2. Position: 
l 
Top ring 
l 
2nd ring 
l 
Oil ring
Offset the piston ring end gaps as
shown. 
a 
Top ring end 
b 
Oil ring end (lower) 
c 
Oil ring end (upper) 
d

Page 199 of 288

YAMAHA TTR90 2001  Owners Manual 4 - 26
ENG
2. Positionner:
lSegment de feu
lSegment d’étanchéité
lSegment racleur d’huile 
Décaler les becs de segment comme illus-
tré.
aBecs du segment de feu
bBecs du segment racleur d’h

Page 200 of 288

YAMAHA TTR90 2001  Owners Manual 4 - 27
ENGCLUTCH
CLUTCH
CRANKCASE COVER (LEFT AND RIGHT)
Extent of removal:1 Crankcase cover (left) removal2 Crankcase cover (right) removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE