Service manual

Page 55 of 151

7-2 Operating Details

General Information

Remove the engine from the frame before servicing the piston or cylinder.

Cylinder Specifications

7-3 Troubleshooting

Low or Unstable Compression Pressure

• Cylinder or piston ring worn out

Knocking or Noise

• Cylinder or piston ring worn out

• Carbon deposits on cylinder head top

• Piston pin hole and piston pin worn out

Smoke in Exhaust Pipe

• Piston or piston ring worn out

• Piston ring installed improperly

• Cylinder or piston damaged

Engine Overheats

• Carbon deposits on cylinder head top

• Cooling pipe clogged or not enough coolant in flow

Item Standard Limit

ID 70.995-71.015 71.100

Cylinder

Bend - 0.050

Top ring 0.015-0.050 0.090

Clearance between piston

rings

2nd ring

0.015-0.050 0.090

Top ring 0.150-0.300 0.500

2nd ring

0.300-0.450 0.650

Ring-end gap

Oil ring side rail 0.200-0.700 -

OD of piston (2nd)

70.430-70.480 70.380

Clearance between piston and cylinder 0.010-0.040 0.100

Piston/ Piston

ring

ID of piston pin boss 17.002-17.008 16.970

OD of piston pin 16.994-17.000 16.960

Clearance between piston and piston pin 0.002-0.014 0.020

ID of connecting rod small-end 17.016-17.034 17.064