Check each piston for scuffing, scoring, wear and other defects. Replace any piston that is defective.
Check each piston ring for breakage, damage and abnormal wear. Replace the defective rings. When the piston requires replacement, its rings shouldalso be replaced.
Check that the piston pin fits in the piston pin hole. Replace any piston and pin assembly that is defective. The piston pin must be pressedsmoothly by hand into the pin hole (at room temperature).
Measure the piston ring side clearance. If the measured value exceeds the service limit, insert a new ring in the ring groove to measure the side clearance. If the clearance still exceeds the service limit, replace the piston and rings together. If it is less than the service limit, replace only thepiston rings.
Piston ring side clearance No.1 : 0.04-0.08 mm (0.0016-0.0031 in.) No.2 : 0.03-0.07 mm (0.0012-0.0028 in.) [Limit] No.1 : 0.1 mm (0.004 in.) No.2 : 0.1 mm (0.004 in.) |
To measure the piston ring end gap, insert a piston ring into the cylinder bore. Position the ring at right angles to the cylinder wall by gently pressing it down with a piston. Measure the gap with a feeler gauge. If thegap exceeds the service limit, replace the piston ring.
Piston ring end gap [Standard dimensions] No.1 : 0.20-0.35 mm (0.0079-0.0138 in.) No.2 : 0.37-0.52 mm (0.0146-0.0205 in.) Oil ring side rail : 0.2-0.7 mm (0.0079-0.0276) [Limit] No.1, No.2 : 0.8 mm (0.031 in.) Oil ring side rail : 1.0 mm (0.039 in) |
Standard | None |
0.25mm (0.010 in.) O.S 0.50mm (0.020 in.) O.S | 25 50 |
The mark can be found on the upper side of the ring next to the end.
When the connecting rod cap is installed, make sure that the cylinder numbers, marked on rod end cap at disassembly, match. When a new connecting rod is installed, make sure that the notches holding the bearing in placeare on the same side.
Replace the connecting rod if it is damaged at either end of the thrust faces. If it has a stratified wear, or if the surface of the insidediameter of the small end is severely rough, replace the rod.
