A powerful motorbike symbolizes that you are a hands-on / spiritual healer. The power of the motorbike is symbolic of the healing power you can channel through your body.
If you dream of a powerful motorbike on the roof of a building it indicates you have a strong intellect.
A motorbike can symbolize your heart and emotions for several reasons. Firstly it requires balance, and balanced expression of feelings is the key to a healthy heart. Secondly, its large wheels (compared to a car) symbolize the heart, as do anything circular in a dream. Thirdly, the engine is the heart of the vehicle.
A powerful motorbike indicates you have spiritual healing power within you. You can use this to channel healing energy into others by placing your hands on them.
A powerful motorbike on the roof of a building also indicates you have a strong mind which gives you the ability to perform absent healing, projection and hypnosis. See Flying.
