What is a motor tic?
Tic
Simple motor tics are typically sudden, brief, meaningless movements that usually involve only one group of muscles, such as eye blinking, head jerking, or shoulder shrugging. Motor tics can be of an endless variety and may include such movements as hand clapping, neck stretching, mouth movements, head, arm or leg jerks, and facial grimacing.
Cush drive
A cush drive is a part of a motorcycle or scooter drive-train that is designed to reduce stress from engine torque damaging other components during gear or throttle changes. A common design used by almost all street motorcycles, it has three major pieces: the wheel, the sprocket assembly, and the rubber damper. The wheel and the sprocket assembly fit together with five or more sections much like two hands woven together. In between the contact of the two assembly are rubber blocks. This makes it so the wheel and the sprocket have a dampening layer between them, and the rubber blocks reduce wear and fatigue of the metal assemblies. Another popular system incorporates metallic compression type coil springs placed between the input and output shafts of the cush drive assembly.