Adjuster sleeve nut

This is the adjuster sleeve nut for the primary chain tensioner setup, showing up in the catalog under both the CHAINCASE AND CHAINS figure and the GEARBOX INNER COVER AND SELECTORS figure. It's part of the mechanism used to take slack out of the primary chain by moving the gearbox in its mounting slots, and it's the piece you turn to set that adjustment. The older number for this same part is 70-4153, so if your parts book or an old parts bag shows that number, it's the same nut you're looking at here under 70-9703 (also seen stamped E9703).