Kawasaki J300 - Service manual > Piston Installation
- Apply molybdenum disulfide oil solution to the oil ring expander, and install the oil ring expander [A] in the bottom piston ring groove so the ends [B] butt together.
- Apply molybdenum disulfide oil solution to the oil ring steel rails, and
install the oil ring steel rails, one above the expander and one below it.
- Spread the rail with your thumbs, but only enough to fit the rail over the piston.
- Release the rail into the bottom piston ring groove.
- The oil ring rails have no "top" or "bottom".
- Apply molybdenum disulfide oil solution to the piston rings.
- Do not mix up the top and second ring.
- Install the top ring [A] so that the "R" mark [B] faces up.
- Install the second ring [C] so that the "RN" mark [D] faces up.
- If a new piston is used, use new piston ring.
- Install the piston with its "IN" mark [A] facing the intake side.
- Fit a new piston pin snap ring into the side of the piston so that the
ring opening [A] does not coincide with the slit [B] of the piston pin hole.
- Apply molybdenum disulfide oil solution to the piston pin and piston journals.
- When installing the piston pin snap ring, compress it only enough to install it and no more.
NOTICE Do not reuse snap rings, as removal weakens and deforms them. They could fall out and score the cylinder wall.
- Install the cylinder (see Cylinder Installation).
Cylinder Wear Inspection
- Since there is a difference in cylinder wear in different directions,
take a side to side and a front to back measurement at each of the 3
locations (total of 6 measurements) shown.
If any of the cylinder inside diameter measurements exceeds the service limit, replace the cylinder.
Cylinder Inside Diameter
Standard: 72.705 - 72.715 mm (2.8624 - 2.8628 in.)
Service Limit: 72.80 mm (2.866 in.)
10 mm (0.4 in.) [A]
50 mm (2.0 in.) [B]
20 mm (0.8 in.) [C]
Piston Wear Inspection
- Measure the outside diameter [A] at a right angle to the direction of
the piston pin.
If the measurement is less than the service limit, replace the piston.
Standard: 72.67 - 72.69 mm (2.8610 - 2.8618 in.)
Service Limit: 72.70 mm (2.862 in.)
Piston/Cylinder Clearance Inspection
The most accurate way to find the piston clearance is by making separate piston and cylinder diameter measurements and then computing the difference between the two values. Measure the piston diameter as just described, and measure the cylinder diameter at the very bottom of the cylinder.
Standard: 0.010 - 0.040 mm (0.0004 - 0.0016 in.)
Service Limit: 0.1 mm (0.0039 in.)
- Whenever the piston or cylinder has been replaced with a new one, the motorcycle must be broken in the same as with a new machine.
Remove the cylinder head (see Cylinder Head Removal). Loosen the water hose clamp screw and disconnect the water hose [A]. Remove: Lower Camshaft Chain Guide [A] Cylinder Bolts [B] Cylinder [C] and Gasket
Check for uneven groove wear by inspecting the ring seating. The rings should fit perfectly parallel to groove surfaces. If not, replace the piston and all the piston rings. With the piston rings in their grooves, make several measurements with a thickness gauge [A] to determine piston ring/groove clearance.