TM 5-3810-307-24-1-2
Use a dial bore gauge, Part No. 3375072, to measure the
cylinder bore diameter.
Measure at 25.0 mm [1.00-inch] below the top of the
crankcase.
Maximum out-of-round is 0.04 mm [0.002-inch]
NOTE
Install new piston rings during rebuild.
If old piston rings are used, follow the instructions listed
below to measure the ring gaps.
Insert one ring at a time into the cylinder bore. Seat the ring
with a piston head squarely 25.0 mm [1.00 inch] below the
top of the crankcase.
QE296 Piston Ring Gaps
MIN
MAX
mm
in
mm
in
Piston Ring (Top) 0.25 [0.010]
0.51
[0.020]
Piston Ring (2nd) 0.25 [0.010]
0.51
[0.020]
Piston Ring (Oil)
0.38 [0.015]
1.40
[0.055]
Inspect the bushing in the crankcase and replace if
damaged.
Change-1 12-41