A flywheel power unit that can be inserted into a variety of machines. The standardization of the power unit means that the more expensive gearing, clutch and flywheel components do not have to be duplicated in each human powered machine. Standard bicycle gearing components can be assembled with a modified clutch for a typical motorcycle to create an inexpensive human powered flywheel power unit. As the user pedals, power is stored in the flywheel. The flywheel axle is connected to a transmission transfer gear that turns a transmission input gear for a transmission with multiple gears in a gearing ratio of 10:1 to 0.8:1 (which is typical for a motorcycle transmission.). A transmission input gear and the transmission transfer gear are approximately a 1:1 gearing ratio. A transmission output gear is attached to the transmission that provides power output from the flywheel only when a clutch within the transmission in engaged. The power unit can be inserted into a wheeled vehicle or used as a power source for a variety of tools.