Kawaski Top-End Kit 550 JS550 1982 1983 1984 1985 1986 1987 1989 1990 1991
Our watercraft top end kit includes new SBT pistons, which are the first piston to be sold with a LIFETIME WARRANTY against defect. SBT pistons are cast using a high-silicone-content aluminum, and anodized on the top surface to increase the operating temperature range and retard normal wear. Sides of piston are graphite coated for minimal wear during break-in procedure; Rings, which are made of chromium-plated ductile iron and are included along with all new wrist-pins, c-clips and wrist-pin bearings; base gaskets & head/head cover gaskets/o-rings, intake gaskets and exhaust gaskets.(Where applicable)
Available in 1mm over size only for this particular application.
Piston to Cylinder Clearance:
The piston size plus the clearance equals the final bore size. For the recommended clearances by make and model, see Table 1. The cylinder first should be bored to within 0.002” of the final bore size. The remaining 0.002” should be removed with a 400 grit cylinder hone. The honing process should be controlled such as to leave a 45 degree crosshatch pattern on the cylinder wall.
Once the cylinder is honed to the final size, all of the ports in the cylinder wall should be chamfered with a file or chamfer tool. The chamfered edge should be cut at approximately a 30 degree angle around the entire port. The cylinder should then be honed with a 400 grit flex hone to apply a uniform finish and to re-establish the 45 degree cross-hatch pattern.
Cylinder Cleaning Process:
Clean cylinders in warm soapy water using a firm plastic brush (such as a tooth brush), then dry, and immediately lubricate with 2-stroke oil. Honing grit tends to reside in the crosshatch and must be scrubbed out. An extremely clean cylinder free of grit is critical in order to avoid “drag marks” and other damage to the cylinder wall after assembly.
Setting the Ring Cap:
Place the piston ring in the cylinder. Use the piston to push the ring approximately 5mm from the top of the cylinder in order to square the ring in the cylinder. Use a feeler gauge to measure the gap between the ends of the ring. If the gap is too small, one end of the ring must be filed. Re-install the ring and measure again to confirm the final dimension. Recommended ring gap clearances are shown in Table 2.
Install the base gasket (we recommend Threebond 1211 as a gasket treatment). Lubricate the wrist pin bearing with 2-stroke oil and install the piston on the connecting rod. The designation mark on the piston crown points in the direction as shown in Table 3. Install the c-clips with the open end in either the 6 or 12 o'clock position. Install the rings onto the piston. Using your hands or a ring compressor, collapse the rings into the ring grooves and install the cylinder. Torque cylinder to proper torque specifications.