Harley-Davidson Topper - Design and Specifications

Design and Specifications

The Topper had a 165 cc (10.1 cu in) single-cylinder two-stroke engine mounted horizontally between the floorboards. The engine required a premixed gasoline/oil mixture. The starter was of the rope-recoil type similar to lawnmowers or the Lambretta E model. Unlike most scooters with enclosed engines, the Topper's engine did not have a cooling fan. It was expected that the low, horizontally-mounted engine would be cooled by air passing under the scooter, but some Toppers developed overheating problems. The engine used a reed valve in its induction system.

The engine powered a continuously variable transmission that included a safety device that did not allow the scooter to move from rest at engine speeds higher than 1800 rpm. Final drive was by an exposed roller chain.

The Topper had 5 inch internal expanding drum brakes on both wheels. The front brake was controlled by a hand lever with a parking brake lock; the rear brake was controlled by a pedal.

The front body, front fender and floorboards of the Topper were made of stamped steel, and the engine cover and body were made of molded fiberglass.