Technical data

Section 04 ENGINE

Sub-Section 02 (TOP END)

040-02-6

NOTE : Replacement cylinder sleeves are

available if necessary. Also, oversize pistons

of 0.25 mm (.010 in) are available for all engines

and oversize pistons of 0.5 mm (.020 in) are avail-

able for the 587 and 717 engines.

Cylinder Taper

Using a cylinder bore gauge, measure cylinder di-

ameter at 16 mm (5/8 in) from top of cylinder just

below auxiliary transfer port, facing exhaust port.

If the difference between readings exceed speci-

fication, cylinder should be rebored and honed or

replaced.

1. Measuring perpendicularly (90

) to piston pin axis

2. Auxiliary transfer port

A. 16 mm (5/8 in)

Cylinder Out of Round

Using a cylinder bore gauge, measure cylinder di-

ameter at 16 mm (5/8 in) from top of cylinder.

Measure diameter in piston pin axis direction then

perpendicularly (90°) to it. If the difference be-

tween readings exceed specification, cylinder

should be rebored and honed or replaced.

1. Measuring in piston pin axis

2. Measuring perpendicularly (90

) to piston pin axis

A. 16 mm (5/8 in)

Piston / Cylinder Wall Clearance

Clearance can be quickly checked with a long feel-

er gauge. Insert feeler gauge in cylinder then slide

piston (without piston rings installed) into cylinder

as shown in the following illustration.

1. Feeler gauge

2. Piston

Or, to accurately determine piston to cylinder wall

clearance, measure piston at 25 mm (1 in) below

skirt end perpendicularly (90°) to piston pin.

F01D8AA

F01D8BA

F01D0MA