Nimbus (motorcycle)

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Stovepipe Nimbus with sidecar

Nimbus „Sport“ with four cylinders, built in 1950

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The Nimbus was a Danish motorcycle produced from 1919 to 1960 by Fisker and Nielsen (Copenhagen, Denmark), also known as the manufacturers of Nilfisk vacuum cleaners.

Two basic models were produced, both with a 750 cc four cylinder engine.

The first Nimbus, Type A & B, had an air-cooled four-cylinder inline engine and a power output of app. 10 hp, transmitting its power to the rear wheel through a shaft drive. Its top speed was around 85 km/h with a sidecar fitted. It was manufactured during the 1920s, and had both front and rear wheel suspension. The very characteristic spine frame - which also was the fuel tank - gave it its nickname "The Stovepipe".

The later Type C (also known as "The Bumblebee", due to its humming exhaust note) was produced in large numbers from 1934 onwards. It had a completely new designed ohv and ohc engine of 18 (later 22) hp, and a frame made from steel strips riveted together, which was shaped to go around the gas tank much like on the pressed steel frames on several other motorcycles of the period. The Nimbus was also the first production motorcycle with a telescopic fork, beating BMW at this with a year.

Many of these machines saw service with the Danish Army, which bought altogether 20% of the total production. The postal service also bough many, using them as late as 1972. The police was a large customer, but phased out theirs much earlier, when it was too slow to keep up with modern cars and motorcycles in the late 1950s and early 1960s. The top speed of a stock solo bike was app. 120 kph, although for brief bursts only. Few were exported.

Innumerable details of "The Bumblebee" were changed during its lifespan, the few major ones being a switch from hand to foot gear change, larger brakes and an improved front fork. Still, the basic design was never updated and, as interest in motorcycles declined in the late 1950s as a consequence of the availability of cheap cars such as the Volkswagen Beetle, production ceased.

Right after WW2 a much improved ohv engine was built and tested. Seeing, however, that the factory had no trouble selling every motorcycle built, it was decided not to make any major investments in new tooling. Instead more minor improvements were made to the existing models, usually making it possible to upgrade older models.

In the 1950s some further prototypes were built, like a four cylinder with a rotary valve and carbon seals (!) as well as a two cylinder model with rear suspension, neither of which reached production. Several prototypes with rear suspension and an earles front fork were also built.

Of app. 12,000 'bumblebees' produced, today more than 4,000 are registered and running in Denmark alone, and likely a few hundreds are used outside of Denmark, mainly in Germany and USA. An estimated further 4,000 or so also exist, either in museums or otherwise not currently registered.

Even today most spare parts are readily available as well as relatively inexpensive. Thanks to the design's inherent reliability, using a Nimbus on a daily basis is still considered easy and economical. Nevertheless (and with some notable exceptions), today most Nimbus owners rarely ride more than a few thousand kilometers a year. Also, as the Nimbus often came from the factory with a sidecar attached, many of the ones on the road have recently been fitted with one such.

By the way, the blue Nimbus on the picture has not been built as a "Sport", as it has the low slung exhaust pipe of the "Standard" model. It has a military style headlamp and speedometer, and a non-stock Lucas tail light & license plate holder.