Loose valve seats are a common problem in recent generations of the Whizzer bicycle motor, as are corrosion problems in early models due to the pot metal construction of the crankcase. Whizzer motors also have a tendency to overheat quickly due to their cylinder design. Whizzer motors produced since 2005 use a different cylinder construction and materials that address many of the problems that are common among earlier versions of these engines.Continue Reading
The Whizzer bicycle motor was first produced in 1939 as an engine that was added to a bicycle to produce a lightweight, low-power motorcycle. After 1948, Whizzer began shipping complete packages including motorcycles and bicycles, but few of these were pre-assembled from the factory to avoid excise taxes on shipment of complete motorcycles. These engines rarely produced more than 3 horsepower and were constructed of relatively cheap materials, leading to corrosion problems that are especially evident in the few surviving early models that were not scrupulously maintained by collectors. Production largely ceased after the 1950s.
The Whizzer name was revived in the early 1990s, and a new version of the Whizzer motor was offered for sale. While these newer engines use more modern design techniques, the first versions became notorious for overheating and poor overall quality. A new company bought the Whizzer name in 1998 and offered a considerably improved version of the Whizzer motor that still suffered from loose valve seats. The 2005 NE5 engine addressed this problem by pouring the seals into the engine casting rather than pressing them in.Learn more about Vehicles