Motorcycle auxiliary water tank and motorcycle

The utility model discloses a motorcycle auxiliary water tank and a motorcycle with the auxiliary water tank. The motorcycle auxiliary water tank mainly comprises a tank body, a water inlet and a water outlet, and the water inlet and the water outlet are formed in the tank body. The water outlet of the auxiliary water tank is formed in the side face of the tank body, and an opening of the water outlet is obliquely upward. In the running process of the motorcycle, cooling liquid stored in the tank body can flow out of the water outlet under the action of inner and outer pressure of the auxiliary water tank. Due to the fact that the opening of the water outlet is obliquely upward, when the cooling liquid stops circulating, the cooling liquid flows back into the tank body again under the action of gravity, and water leaked out of the connecting position of the water outlet and a pipeline is reduced.