2006 YAMAHA TTR90 Owners Manual

Page 241 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 23
ENG
Zylinderbohrung “C”47,000–47,005 mm
(1,8504–1,8506 in)
Max. Konizität “T”0,05 mm (0,002 in)
Max. Ovalität “R”0,05 mm (0,002 in)
“C” = größtes Maß unter D
“T” =

Page 242 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 24
ENGCYLINDER AND PISTON
Piston ring
1. Measure:
Ring side clearance
Use a feeler gauge. 
Out of specification → Replace the piston
and rings as a set.
NOTE:
Clean carbon from the piston ring

Page 243 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 24
ENG
Kolbenringe
1. Messen:
Ringnutspiel
(mit einer Fühlerlehre) 
Nicht nach Vorgabe → Kolben samt Kol-
benringen erneuern.
HINWEIS:
Vor der Messung des Ringnutspiels müssen
die Ölkohleabl

Page 244 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 25
ENGCYLINDER AND PISTON
Piston pin
1. Inspect:
Piston pin
Blue discoloration/grooves → 
Replace, then inspect the lubrication sys-
tem.
2. Measure:
Piston pin outside diameter
Piston pin bo

Page 245 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 25
ENG
Kolbenbolzen
1. Kontrollieren:
Kolbenbolzen
Blaubrüchig/riefig → 
Kolbenbolzen erneuern und Schmiersys-
tem kontrollieren.
2. Messen:
Kolbenbolzen-Durchmesser
Kolbenbolzenaugen-Durchm

Page 246 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 26
ENGCYLINDER AND PISTON
2. Position:
Top ring
2nd ring
Oil ring
Offset the piston ring end gaps as shown.
aTop ring end
bOil ring end (lower)
cOil ring end (upper)
d2nd ring end
3. Install:


Page 247 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 26
ENG
2. Anordnen:
1. Kompressionsring (Topring)
2. Kompressionsring
Ölabstreifring
Die Ringspalte, wie in der Abbildung
gezeigt, versetzen.
aSpalt des 1. Kompressionsrings
bSpalt der unteren

Page 248 of 390

YAMAHA TTR90 2006  Owners Manual 4 - 27
ENGCLUTCH
CLUTCH
CRANKCASE COVER (LEFT AND RIGHT)
Extent of removal:
1 Crankcase cover (left) removal
2 Crankcase cover (right) removal
Extent of removal Order Part name Q’ty Remarks
CRANKCAS