Yamaha 2011 YZ250, Owner'S Manual

Page: 109 / 174

4-45
CRANKCASE AND CRANKSHAFT
INSTALLING THE CRANKCASE
BEARING
1. Install:
• Bearing "1"
To left and right crankcase.
• Apply the engine oil on the bearing.
• Install the bearing by pressing its
outer race parallel.
INSTALLING THE OIL SEAL
1. Install:
• Oil seal (left) "1"
• Oil seal (right) "2"
• Apply the lithium soap base grease
on the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
INSTALLING THE CRANKSHAFT
1. Install:
• Crankshaft "1"
Use the crankshaft installing tools
"2", "3", "4".
• Hold the connecting rod at top dead
center with one hand while turning
the nut of the installing tool with the
other. Operate the installing tool un-
til the crankshaft bottoms against
the bearing.
• Before installing the crankshaft,
clean the contacting surface of
crankcase.
• Apply the lithium soap base grease
on the oil seal lip.
Do not use a hammer to drive in
the crankshaft.
A. For USA and CDN
B. Except for USA and CDN
2. Check:
• Shifter operation
• Transmission operation
Unsmooth operation
→
Repair.
3. Install:
• O-ring "1"
To right crankcase "2".
4. Apply:
• Sealant
On the right crankcase "1"
Clean the contacting surface of left
and right crankcase before applying
the sealant.
5. Install:
• Dowel pin "1"
• Right crankcase "2"
To right crankcase "3".
• Fit the right crankcase onto the left
crankcase. Tap lightly on the case
with soft hammer.
• When installing the crankcase, the
connecting rod should be posi-
tioned at TDC (top dead center).
In order to prevent the oil seal lip
"a" from being turned up or dam-
aged, wrap a vinyl tape or the like
"b" around the right end of the
crankshaft and apply the lithium
soap base grease over the tape.
Standard <Limit>
Runout
limit: 0.030 mm
(0.0012 in)
0.050
mm
(0.0020
in)
Small
end free
play: 0.40–1.00
mm (0.02–
0.04 in)
2.0 mm
(0.08 in)
Side
clear-
ance:
0.250–0.750
mm
(0.0098–
0.0295 in)
—
Crack
width:
59.95–60.00
mm (2.360–
2.362 in)
—
Crankshaft installing pot
"2":
YU-90058/90890-01274
Crankshaft installing bolt
"3":
YU-90060/90890-01275
Adapter "4":
YU-90063/90890-01278
Yamaha bond No.1215:
90890-85505
(Three bond No.1215®)