Yamaha XS650SE, Shop Manual

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B
4. All camshaft bearings should be removed,
cleaned, dried, and the races visually
checked for pits, rust spots or chatter
marks where the balls have dragged, If
any of these conditions exists the bear-
ing(s) should be replaced.
G.Cam chain, sprocket and dampers
1. Cam chain
Except in cases of oil starvation, the cam
chain wears very little. If the cam chain
has stretched excessively and it is difficult
to keep the proper cam chain tension, the
chain should be replaced.
2. Cam sprockets
Check cam sprockets for obvious wear.
3. Cam chain dampers
Inspect the two vertical (slipper-type)
dampers for excessive wear. Any that
shows excessive wear should be replaced.
Worn dampers may indicate an impro-
perly adjusted or worn-out cam chain,
H. Cylinder
1. Inspect the cylinder walls for scratches. If
vertical scratches are evident, the cylinder
wall should be rebored or the cylinder
should be replaced.
2. Measure cylinder wall wear as shown. If
wear is excessive, compression pressure
will decrease. Rebore the cylinder wall
and replace the piston and piston rings.
Cylinder wear should be measured at
three depths with a cylinder bore gauge.
(See illustration.)
Standard
Wear
Cylinder
If the cylinder wall is worn more than
wear limit, it should be rebored.
I. Piston and piston rings
1. Piston
a. Measure the outside diameter of the
piston at the piston skirt.
Measurement should be made at a point
10 mm (0.394 in) above the bottom edge
of the piston. Place the micrometer at
right angles to the piston pin.
Standard: 74.96, 74.97 mm
(2.951, 2.952 in)
Oversize 1: 75.25 mm (2.963 in)
Oversize 2: 75.50 mm (2.972 in)
Oversize 3: 75.75 mm (2.982 in)
Oversize 4: 76.00 mm (2.992 in)
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