1. Using a sharp knife, trim away any part of the center case gasket that protrudes from between the cases at the cylinder mounting bosses. Squirt a small amount of oil into the two main bearing oil holes drilled in the transfer port cutouts.
Installing The Top End Components
2. Turn the crankshaft until the connecting rod is at top dead center (T.D.C.). Wrap a clean shop rag around the rod, covering the opening of the crankcase. This will prevent any parts or foreign material from falling into the c ran kcase while you are assembling the components.
3. The piston, wrist pin, wrist pin bearing, and connecting rod are all coded to allow a perfect select fit upon assembly. It is important to pay careful attention to this coding, and assemble the top end using the correct components.
4. You will notice that there is a dab of paint on one side of the connecting rod just below the wrist pin boss. This denotes the code for the connecting rod. The paint may be either yellow, green, or red.
The piston has a dab of either black or white paint on the underside of the piston, on one of the wrist pin bosses. This denotes the code for the piston.
The wristpin has a small dab of paint inside the hole on one end. This
can also be either black or white.
The wrist pin bearings have no identifying marks on them. They are all catalogued by the same number and use a suffix (0-2, 2-4, etc.) after the part number for each different size. There are four sizes.
5. To determine which parts you need is very easy, using the color code chart (Fig. 109). First, find out what color code is used on the piston you have selected for reassembly. The color code of the wrist pin and the color code of the piston must always be the same. If you purchased a complete piston assembly, the wrist pin and piston were correctly matched at the factory. If you purchased the piston and wrist pin separately, the colors on both must be the same.
6. Next, determine which color coding is used on your connecting rod, then refer to the chart to determine which wrist pin bearing you will need.
NOTE: If you are in doubt as to which wrist pin bearing you possess, put the bearing inside the connecting rod and insert the wrist pin into it. The pin should be easy to slide through the bearing. Once you have the pin in place, hold the rod firmly with your fingers and try to wiggle the wrist pin inside the bearing. If any play is detectable between the pin and bearing, or if any force is required to push the pin into it, you have the wrong bearing and it should not be used.
7. After you have correctly selected the proper top end components, take a new cylinder base gasket and carefully slide it down over the studs, into place on the crankcase. Inspect the area around the transfer port cutouts closely and if any of the gasket