Service Manual

5.49
ENGINE
5
Piston Ring Installed Gap
1. Place each piston ring (A) inside the cylinder (B) (from
cylinder head side of crankcase). Use the piston to push the
ring squarely into cylinder, as shown below.
2. Measure installed gap with a feeler gauge (C) at both the
top and bottom of the cylinder.
IMPORTANT: A difference between top and bottom
end gap measurements is a general indication of
cylinder taper (wear). The cylinder should be
measured for taper and out of round.
Piston Pin Bore Inspection
1. Measure piston pin bore.
Cylinder Inspection
1. Remove all gasket material from gasket surface.
2. Lay a straight edge across cylinders (upper crankcase).
3. Use a thickness gauge to measure gap between straightedge
and gasket surface. Measure at outer edges and center,
repeating measurements with straightedge laid diagonally.
4. Inspect cylinder for wear, scratches, or damage.
IMPORTANT: DO NOT hone the cylinders or attempt
to repair a damaged cylinder by honing. See “Honing
- Important Information” on page 5.50
5. Inspect taper and out of round with a dial bore gauge.
Piston Ring Installed Gap
Top: 0.014" ± 0.008" (0.36 ± 0.20 mm)
Second: 0.014" ± 0.008" (0.36 ± 0.20 mm)
Oil Control Rails:
0.0196" ± 0.010" (0.50 ± 0.25mm)
Piston Pin Bore:
0.7877" ± .0002" (20.007 ± .004 mm)
25-50 mm
A
B
C
Head gasket
surface
= In. / mm.
Cylinder Warp: .002" (0.05 mm) Max.