Retention Nut for the Starter Ring Gear for Rotax Max Kart Engines. This nut is M20 in size, with a 1.5mm thread pitch spacing.
Each nut is designed to thread on to the end of the crankshaft, and hold the starter ring gear in place during operation of the engine.
Point Karting recommends utilizing Permatex "Sleeve Retainer" or "Green" Loctite to ensure this nut stays in place.