Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and Reassembly
Pistons, Piston Rings, Connecting Rods and Cylinders Disassembly and ReassemblyDisassembly
1. Using piston ring expander, remove two compression rings (Top and 2nd) and oil ring from piston.
2. Remove piston pin from connecting rod.
^ Ease out piston pin circlips (1), as shown.
^ Force piston pin out.
Reassembly
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 as follows.
1. Each piston (1) has stamped number (2) as shown. It represents outer diameter of piston.
2. There are also painted color (3) of red or blue on cylinder block (2) as shown.
3. Stamped number on piston and painted color (or stamped number) on cylinder block should 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).
Also, a letter "A" or "B" is stamped on piston head but ordinarily it is not necessary to discriminate each piston by this letter.
Piston outer diameter and cylinder bore diameter specification
Piston outer diameter and cylinder bore diameter specification:
4. Install piston pin to piston (1) and connecting rod (3):
After applying engine oil to piston pin, piston pin holes in piston and inner surface of connecting rod small end, fit connecting rod to piston as shown in figure and insert piston pin to piston and connecting rod, and install piston pin circlips.
NOTE:
^ Oil hole (4) comes on intake side.
^ Circlip (5) should be installed so that circlip end gap comes within such range as indicated by arrow.
5. Install piston rings to piston:
^ As indicated in figure at the left, 1st and 2nd rings have "R" mark respectively. When installing these piston rings to piston, direct marked side of each ring toward top of piston.
^ 1st ring (1) differs from 2nd ring (2) in thickness, shape and color 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 two rails.
6. After installing three rings (1st, 2nd and oil rings), distribute their end gaps as shown in figure.
