Motorpsycho is an individual who rides their motorcycle with complete and total disregard for the safety of themselves or others, or an individual who rides purely to satisfy their own ego, refusing to shift gears because revving their engine sounds so cool.

Motorpsycho就是指那种骑起摩托车来就完全不顾自己和他人安危的人，或是那些骑摩托车纯粹是为了满足自我表现意愿的人，他们在骑行过程中不愿换挡，因为发动机启动的声音听起来实在太酷了。这种人可称之为“摩托狂人”。

For example:

The guy who won't shift out of first and pops wheelies in my neighborhood on the same street where kids play and ride their bikes is a total motorpsycho. (Source: urbandictionary.com)

那家伙就是个摩托狂人。他在我家附近孩子们玩耍和骑自行车的那条街上挂着一档骑摩托车，而且还玩翘头。