47. There are two OSSA special tools used for the installation of the primary case; tool No. 121-950, selector shaft "0" ring protector, and tool No. 121-951, kickstarter shaft "0" ring protector (Fig. 106). These tools are used to keep the splines on the shafts from damaging the "0" rings when the primary case is passed over them. To install the tools, grasp the large knurled part in one hand and push the sliding center bar all the way inward with the other hand. Hold the tool in this position and push it into the appropriate hole in the primary case. Then, when installing the primary case, the ends of the shafts will push the center bar out of the tool, but the "0" ring will remain shielded until the spline has passed it.
48. Fit the primary case to the engine pushing or tapping it gently
down over th kickstarter shaft and selector shaft (Fig. 107) Tap the case
gently with a plastic or rawhid mallet to seat it against the engine case.