What is a 4 stroke bike running on if it has no 4stroke in it?

A 4-stroke bike typically runs on gasoline, which is a common fuel for internal combustion engines. If it has no 4-stroke engine components, it might be powered by an alternative engine type, such as a 2-stroke engine or an electric motor. In the case of a 2-stroke engine, the fuel is usually a mixture of gasoline and oil. An electric bike would rely on batteries for power instead of any fuel.