Piston diameter
- Using a micrometer, measure the piston diameter at 10 mm (0.4 in) А from the piston skirt end.
- If the measurement is less than the limit, replace the piston.
Piston diameter:
- Service Limit: 111.880 mm (4.4047 in) at 10 mm (0.4 in) from the skirt end
- 09900-20210: Micrometer (100 - 125 mm)
Piston-to-cylinder clearance
- Subtract the piston diameter from the cylinder bore diameter. (3-41)
- If the piston-to-cylinder clearance exceeds the service limit, replace the cylinder or the piston, or both.
Piston-to-cylinder clearance:
Service Limit: 0.120 mm (0.0047 in)
Piston pin and pin bore
- Measure the piston pin bore diameter using the small bore gauge.
- If the measurement is out of specification, replace the piston.
Piston pin bore I.D.:
- Service Limit: 23.030 mm (0.9067 in)
- 09900-20602: Dial gauge (1/1000 mm)
- 09900-22403: Small bore gauge (18 - 35 mm)
- Measure the piston pin outside diameter at three positions using the micrometer.
- If any of the measurements is out of specification, replace the piston pin.
Piston pin O.D.:
- Service Limit: 22.980 mm (0.9047 in)
- 09900-20205: Micrometer (0 - 25 mm)
Piston ring-to-groove clearance
- Measure the side clearances of the 1st and 2nd piston rings using the thickness gauge.
- If any of the clearances exceeds the limit, replace both the piston and piston rings.
- 09900-20803: Thickness gauge
- 09900-20205: Micrometer (0 - 25 mm)
Piston ring-to-groove clearance:
Service Limit (1st): 0.180 mm (0.0071 in) (2nd): 0.150 mm (0.0059 in)
Piston ring groove width:
Standard (1st): 0.93 - 0.95 mm (0.0366 - 0.0374 in): 1.55 - 1.57 mm (0.0610 - 0.0618 in) (2nd): 1.21 - 1.23 mm (0.0476 - 0.0484 in) (Oil): 2.51 - 2.53 mm (0.0988 - 0.0996 in)
Piston ring thickness:
Standard (1st): 0.86 - 0.91 mm (0.034 - 0.036 in): 1.38 - 1.40 mm (0.054 - 0.055 in) (2nd): 1.17 - 1.19 mm (0.046 - 0.047 in)
Piston ring free end gap and piston ring end gap
- Measure the piston ring free end gap using the vernier calipers.
- Next, fit the piston ring squarely into the cylinder and measure the piston ring end gap using the thickness gauge.
- If any of the measurements exceeds the service limit, replace the piston ring with a new one.
Piston ring free end gap:
- Service Limit (1st): 12.6 mm (0.50 in) (2nd): 11.6 mm (0.46 in)
- 09900-20101: Vernier calipers
Piston ring end gap:
- Service Limit (1st): 0.50 mm (0.020° in) (2nd): 0.50 mm (0.020 in)
- 09900-20803: Thickness gauge