Yamaha XS650SE, Shop Manual

Page: 31 / 215

b. Determine piston clearance as follows:
Example:
75.02 mm
-74.97 mm
=0.05 mm piston clearance
c. Piston ring/ring groove fit must have
correct clearance. If the piston and ring
have already been used, the ring must be
removed and the ring groove cleaned of
carbon. The rings should then be rein
stalled. Use a feeler gauge to measure the
gap between the ring and the land.
1 0 . 0 0 1 2 - 0 . 0 0 2 8 i n )
2. Piston ring
a. The oversize top and middle ring sizes are
stamped on top of the ring.
b. Push the ring into the bore and check end
gap clearance with a feeler gauge.
NOTE:
The end gap on the expander spacer of
the oil control ring is unmeasureable. If
oil control ring rails show excessive gap,
all three components should be replaced.
Standard Limit
0.2 0.4 mm 1.0 mm
ring
(0.0079 0.016 in) (0.039 in)
Oil control 0.2 0.9 mm
Visual
(Rails)
(0.0079 0.0354 in) inspection
J. Piston pin
1.
2.
Apply a light film of oil to pin. install in
connecting rod small end. Check for play.
There should be no noticeable vertical
play. If play exists, check connecting rod
small end for wear. Replace pin and con-
necting rod as required.
The piston pin should have no noticeable
free play in piston. If the piston pin is
loose, replace the pin and/or the piston.
K. Crankshaft
1. Main bearing and big end bearing visually
inspect all friction surfaces for obvious
pits, scratches, chatter marks, or rust. Re-
place it if necessary.
2. Small end play(A)
Maximum allowable tolerance:
2.0 mm (0.079 in)
3. Big end side clearance(B)
Standard clearance:
0.15 0.4 mm (0.0059 0.016 in)
4. Crankshaft run out(C)
Mount the crankshaft in V-blocks and
check for run out using a dial gauge.
Run out limit: 0.05 mm (0.002 in)
L. Oil pump
1. Check the clearance between housing and
outer rotor.
Standard clearance:
0.10 0.18 mm (0.0039 0.0071 in)
27