ENGINE TOP END 5-35 Cylinder, Piston

Piston Diameter

• Measure the outside diameter [A] of each piston 5 mm [B] up from the bottom of the piston at a right angle to the direction of the piston pin.

• If the measurement is under the service limit, replace the piston.

Piston Diameter
Standard: 73.942 ~ 73.957 mm (2.9111 ~ 2.9117 in.)

Service Limit: 73.79 mm (2.9051 in.)

Boring, Honing When boring and honing a cylinder, note the following:

OThere is one oversize piston available. Oversize pistons require oversize rings. Oversize pistons and rings avail­able are 0.5 mm larger than standard.

OBefore boring a cylinder, first measure the exact diameter of the oversize piston, and then, according to the standard clearance in the Service Data Section, determine the re-bore diameter. However, if the amount of boring neces­sary would make the inside diameter greater than 0.5 mm oversize, the cylinder block must be replaced.

OCylinder inside diameter must not vary more than 0.01 mm at any point.

OBe wary of measurements taken immediately after boring since the heat affects cylinder diameter.

OIn the case of a rebored cylinder and oversize piston, the service limit for the cylinder is the diameter that the cylin­der was bored to plus 0.1 mm and the service limit for the piston is the oversize piston original diameter minus 0.15 mm. If the exact figure for the rebored diameter is unknown, it can be roughly determined by measuring the diameter at the base of the cylinder.

ONever separate the liner from the cylinder, because the top surface of cylinder and liner is machined at the factory as an assembly.