Cylinder Boring

1. When boring the cylinder bore to oversize, keep the specified clearance between the oversize piston and the bore, and make sure that all pistons used are of the same oversize.
2. The standard measurement of the piston outside diameter is taken at a level 12.00 mm (0.4700 inch) above the bottom of the piston skirt and across the thrust faces.
3. Refer to standard values below when boring engine cylinders.



Standard Values:
Cylinder bore 82.00-82.03 mm (3.2283-3.2295 inch)
Out-of-round and taper Less Than 0.01 mm (0.0004 inch)
Clearance with piston 0.025-0.045 mm (0.0008-0.0016 inch)
Piston O.D:
Standard Size 81.97-82.00 mm (3.2271-3.2283 inch)
Service (Over) size
1st. 0.25 mm (0.0100 inch)
2nd. 0.50 mm (0.0200 inch)
3rd. 0.75 mm (0.0300 inch)
4th. 1.00 mm (0.0390 inch)
Piston service (over) size markings:
1st. O.S: 0.25
2nd. O.S: 0.50
3rd. O.S: 0.75
4th. O.S: 1.00