Piston, Piston Ring and Connecting Rod Disassembly and Reassembly

Piston, Piston Ring and Connecting Rod Disassembly and Reassembly
Reference: Piston, Piston Ring and Connecting Rod Removal and Installation

CAUTION:
Parts must be reassembled in the position where they were. Keep the following as a group for each cylinder:
^ Piston
^ Piston pin
^ Piston ring
^ Connecting rod
^ Connecting rod bearing
^ Connecting rod bearing cap

Disassembly
1) Use a piston ring expander to remove 1st and 2nd rings and oil ring from piston.
2) Remove piston pin from connecting rod as follows.
a) Remove piston pin circlips (1), as shown.





b) Remove piston pin.





Reassembly
Reference: Cylinder, Piston and Piston Ring Inspection
Reference: Piston Pins and Connecting Rods Inspection
Reference: Crankshaft Pin and Connecting Rod Bearings Inspection

CAUTION:
^ Apply engine oil to the following parts:
- Piston pin hole
- Piston pin
- Connecting rod small-end bore
^ Reassemble the following parts in the position where they were:
- Piston
- Piston pin
- Piston ring
- Connecting rod
- Connecting rod bearing
- Connecting rod bearing cap

NOTE:
Two sizes of piston are available as standard size spare part so as to ensure proper piston-to-cylinder clearance. When installing a standard size piston, make sure to match piston with cylinder.

1) To replace piston, select proper piston using the following procedures:
a) Check stamped number (2) on piston (1) as shown in figure.
b) Check stamped number (4) on lower crankcase (3) as shown in figure.








c) Stamped number on piston and stamped number on lower crankcase correspond with each other.
Select proper piston referring the following table.

Piston selection table





2) Use a suitable tool to remove carbon deposit from piston head and ring grooves.
3) Assemble piston pin, piston (1) and connecting rod (2) as follows.
a) Apply engine oil to piston pin, piston pin hole in piston and connecting rod.
b) Fit connecting rod to piston.

NOTE:
Be sure to position front mark (4) on piston and oil hole (5) of connecting rod (2) at specified position as shown in figure.

c) Insert piston pin to piston and connecting rod.
d) Install new piston pin circlips (3).

NOTE:
Install circlip so that circlip end gap comes within the range indicated by arrow (6).





4) Install piston rings to piston noting the following points:
^ As indicated in figure, 1st and 2nd rings have discrimination mark (1) respectively. When installing these piston rings to piston, direct discrimination mark side of each ring toward top of piston.
^ 1st ring (2) differs from 2nd ring (3) in thickness, shape and color of surface contacting cylinder wall. Refer to the figure to distinguish 1st ring from 2nd ring.
^ When installing oil ring (4), install spacer first, and then install two rails.





5) After installing three rings (1st, 2nd and oil rings), distribute their end gaps as shown in figure.