Cylinder Bore; Pistons; Piston Rings - BRP E250DHLSCS Service Manual

Cylinder Bore

Use Cylinder Bore Gauge, P/N 771310, to inspect
each cylinder bore for an out-of-round, oversize,
or tapered condition. Be sure the gauge is per-
fectly square in the bore when measuring.
Measure as shown
Measure each cylinder in at least two areas. Each
area should be measured twice. The difference
between the two measurements in each area is
the cylinder out-of-round dimension.
The cylinder must not be out-of-round by more
•
than 0.004 in. (0.10 mm).
The dimensional difference between the two
areas is cylinder taper.
The cylinder taper must not exceed 0.002 in.
•
(0.05 mm).
1
1. Cylinder taper
The difference between the measurements and
standard bore is cylinder oversize. For dimen-
sions, refer to SERVICE SPECIFICATIONS on
p. 10.
The cylinder must not be oversized by more
•
than 0.003 in. (0.08 mm).

Pistons

Visually inspect pistons for signs of abnormal
wear, scuffing, cracks, or burning.

Piston Rings

For new ring sets, place each ring separately in its
respective bore. Use a piston to square the ring in
the cylinder. Use a feeler gauge to measure the
ring end gap.
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Ring end gap should be:
0.022 to 0.028 in. (0.56 to 0.71 mm)
•
IMPORTANT:
mately 0.003 in. (0.076 mm) for each 0.001 in.
(0.025 mm) increase in cylinder bore diameter.
DO NOT exceed cylinder oversize dimension.
Use a machinist's straightedge to check for proper
ring clearance. Position piston rings on piston.
Push rings into groove and hold straightedge
against the side of the piston. Rings must be even
or just below the surface of piston. Rings must
move freely in piston ring groove.
DR1119
POWERHEAD
POWERHEAD INSPECTION
Ring end gap increases approxi-
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