A motorcycle chain is a metallic chain that is used to transmit power from the engine to the rear wheel. The chain, like many other parts, wears with age and use. As it wears it becomes loose and no longer fits tightly to the front and rear sprockets. This can affect performance and wear down the sprocket teeth. If the chain becomes too worn it can snap. If this happens while riding it can be extremely dangerous. Good care of your motorcycle drive chain is vital and should include cleaning, adjusting, and where necessary lubricating it.