Yanmar 1GM User Manual page 87

SINGLE-CYLINDER ENGINES
Piston
Connecting
rod
Bearings
Rod cap
Bolts
2. Remove the clip from each side of the piston pin bore
(Figure 33) with a small screwdriver or scribe. Hold a
thumb over one edge of the clip when removing it to pre-
vent the clip from springing out.
3. Use a wooden dowel or suitable tool and push out the
piston pin. If the pin is difficult to remove, heat the piston
81
with a hair dryer. Separate the piston from the connecting
rod.
Piston/Cylinder Bore Check
Unless precision measuring equipment is available,
have this procedure done by a machine shop.
1. Measure the piston diameter with a micrometer (Fig-
ure 34) at a right angle to the piston pin bore 9 mm (0.35
in.) from the bottom of the piston skirt.
2. Measure the cylinder bore diameter at several points
with a bore gauge (Figure 35). Figure 36 shows the
points of normal cylinder wear. If dimension A exceeds
dimension B by more than 0.02 mm (0.0008 in.), rebore
the cylinder and install a new piston/ring assembly.