Overhaul

Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and Reassembly

Disassembly
1. Using piston ring expander, remove two compression rings (Top and 2nd) and oil ring from piston.
2. Remove piston pin from connecting rod.
a) Ease out piston pin circlips (1) as shown in figure.





b) Force piston pin out.





Reassembly

1. 2 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 as follows.
a) Each piston (8) has stamped number (9) on its piston head. It represents outer diameter of piston.
b) There are also stamped numbers (10) or painted color (10) on cylinder block as shown in figure.
c) Stamped number on piston and painted color (stamped number) on cylinder block must correspond. That is, install number "2" stamped piston to cylinder which is identified with blue painted (or "2" stamped) and a number "1" piston to cylinder with red painted (or "1" stamped).

Piston outer diameter and cylinder bore diameter





Piston-to-cylinder clearance
0.02 - 0.04 mm (0.0008 - 0.0015 in.)








2. Install piston pin to piston and connecting rod:

After applying engine oil to piston pin and piston pin holes in piston (1) and connecting rod (3), fit connecting rod to piston as shown in figure and insert piston pin to piston and connecting rod, and install piston pin circlips.

NOTE:
"5930" mark on connecting rod must face toward crankshaft pulley side.








NOTE:
^ Install circlip (6) with its cut part facing as shown in figure.
^ Install so that circlip end gap comes within such range as indicated by arrow.








3. Install piston rings to piston:
^ As shown in figure, 1st (1) and 2nd rings (2) have "RN" or "R" mark respectively. When installing these piston rings to piston, direct marked side of each ring toward top of piston.
^ 1st rings differs from 2nd ring in thickness, shape of surface contacting cylinder wall.
Distinguish 1st ring from 2nd ring by referring to figure.
^ When installing oil ring (3), install spacer first and then 2 rails.








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