A Whizzer bicycle is a type of motorbike that originally came from the Los Angeles-based company Breene-Taylor Engineering, which initially manufactured airplane parts. While modern Whizzer bicycles come as complete models, Breene-Taylor Engineering at first only manufactured the Whizzer Model D bicycle motor, a small air-cooled four-cylinder motor that could attach to an existing bicycle with a provided kit. Whizzer bicycles currently come as pre-assembled bikes with Schwinn-style bicycle frames and pre-attached motors as of 2015.
In 2009, the Whizzer Motorbike company went on a hiatus from manufacturing its bicycles, though it continues to sell Whizzer bicycle accessories, parts and wear. Because of this, the term "Whizzer bicycle" may also simply refer to a bicycle that has been outfitted with a Whizzer bicycle motor or additional motorized parts such as a Whizzer fuel tank or a Whizzer transmission, clutch and starter system.
Most models of Whizzer bicycles are typically classified as mopeds because their bicycle-style frames allow for pedalling while the Whizzer engines provide a means of motorized transportation. The motorbikes can reach top speeds of up to 50 miles per hour. Because of this classification as a motorized bicycle or moped, Whizzer drivers are required to have licenses to operate Whizzer bicycles on public roads.