A bank angle sensor is a safety device that detects if a motorbike is leaning on an extreme angle or if the bike has been dropped, and subsequently cuts power to the engine. It is a crucial aspect of the bike. If it is malfunctioning, the bike will be pulled from the market, as was the case with the 2011/2010 Honda VT750C model and the 2011 Honda VT750C2B model.
The bank angle sensor is comprised of a small metal ball that is placed between two electrical contacts that connects the power circuit and the ignition coil. When the bike leans at a dangerous angle or is dropped, that ball rolls from between the two contacts and the circuit is broken. The interrupted circuit cuts power to the ignition coil, which then stops the engine.
The bank angle sensor is a safety device designed to minimize the risks of a motorcyclist being dragged back into the motorbike by a fast spinning wheel when the bike is dropped at speed. Examples of these accidents can be seen in Moto GP Racing where the bank angle sensor has been modified to allow the riders to lean down closer to the curb. When the riders get too low and the motorcycle slips out from under them, the riders can be seen kicking the bike away as a final measure to escape the wheel from dragging their arms and legs back into the motorcycle and causing even more serious injury.