1963 Harley-Davidson Topper
Capitalizing on the late-1950s popularity of scooters, Harley-Davidson brought out the Topper in 1960. This is the only motor scooter that H-D ever produced in their 110+ year history. Approximately 3,000 of these scooters were built during the model run from 1960 through 1965, and less than 100 are currently believed to remain worldwide.
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 lawn mowers. 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 had a bore and stroke of 2.375 in X 2.281 in (60.3 mm X 57.9 mm). The AU engine used a smaller-based manifold than the A and AH models, but all Topper engines used the same reed valve plate induction assembly. The piston and rings were the same as the Harley lightweight (1953 to 1959 ST and 1960 Super 10) engines. Some other internal parts were interchangeable as well.
The engine powered a continuously variable transmission called "Scootaway Drive." The transmission gear ratio ranged from 18:1 to 6:1. The system 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 on the left handlebar] with a parking brake lock; the rear brake was controlled by a pedal.
The Topper used a leading link front suspension and a rear swingarm with two extension springs. The tires were sized at 4.00 X 12.00. The wheelbase measured 51.5 inches. The 1.7 gallon fuel tank was enough to support a good distance because the scooter made 80 to 100 miles per gallon.
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. Storage space was provided under the seat; the manufacturer suggested storing extra containers of two-stroke oil there.
The main complaint from early Topper owners was with the Scootaway Drive continuously variable transmission. Road grime would get into the transmission and cause the belt to slip. A new transmission, with the primary drive sealed in an oil bath, was introduced in 1961.
The Topper H was introduced in 1961 (sold through 1965) with a new alloy cylinder head that increased the compression ratio to 8.0:1, a reusable foam air filter, and revisions to the cylinder ports and air intake tube. The engine developed 9 horsepower and could propel the 247 pound scooter to 46 mph.
A detuned version of the Topper (6.6:1 CR) was also available, with the power restricted to 5 hp. This was advertised as the "Topper U". The detuned Topper was made to comply with laws in some states in the United States that allowed motorcycles with rated engine power below a stated maximum to be operated without a license or to be operated on a special license by riders at a younger age than would be allowed a regular motorcycle license.
The Harley-Davidson Topper motorcycle was among the casualties when the short-lived scooter craze subsided and Japanese brands began to take an ever-growing share of the American motorcycle market.
Interesting facts: In while testing in 1959, a Topper was ridden from Bakersfield, California to Death Valley and back without repair or adjustments requiring tools. The route went through Trona, through the Mojave Desert to Stovepipe Wells, on to Badwater Basin, the lowest point in North America at 282 ft (86 m) below sea level, then to Whitney Portal, 7,851 feet (2,393 m) above sea level on the side of Mount Whitney, after which it returned to Bakersfield.