... and deeply technical conversation. The main classifications of gear:1. Pinion gear2. Ring gear3. Duplicate gear4. Sprocket5. ... ring. Motorcycle:Driven gear and parts, sprocket, starter pawl, ratchet, star gear, duplicate gear, pinion gear, gear ring, variable gear, pushrod cam, ... exhaust valve seat. Oil pump parts:Oil pum gear, gear hub, various rotors, inner rotor and outer ...