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1938 Nimbus 750 Straight 4 – Motorworld


Posted on April 1, 2017 by Andrew in Classic. 31 comments

We’ve been told more than once by keyboard warriors that our taste in bikes sucks. But in a welcome twist of fate, that comment is absolutely correct for tonight’s ride. Why? Because this classically beautiful bike was manufactured by the industrial powerhouse of Fisker & Nielsen in Copenhagen; better known to you and I as the Nilfisk vacuum company. And if there’s ever a motorcycle we’d like to see brought back to life by its modern patent owners, it’d be this one. So direct from Russia’s Motorworld by V. Sheyanov, here’s a mint condition, cherry red 1938 Nimbus 750.

Many early 20th Century European automotive manufacturers started with the production of bicycles, planes and even small arms. But the “Fisker & Nielsen” company, founded in 1906 by Peder Andersen Fisker and Hans Marius Nielsen, became widely known as the first manufacturer of vacuum cleaners in Europe.

But luckily, the ambitions of the founders didn’t begin and end with household appliances. And so in 1919, the company released its first motorcycle, named the ‘Nimbus. Far from being a also-ran bike from a company looking to expand its product range, the ‘A’ model Nimbus was loaded with innovation (and a little fashion) that saw it become an instant hit.

Replaced by the ‘B’ model in 1923, its popularity continued until production suddenly  ceased in 1927, after a decision was made by the company to focus on expanding its range of domestic products.

Then in 1934, the company unexpectedly announced a new model  ‘C’ Nimbus. The design of the new machine may have superficially resembled the previous models by the fact that the inline “four” was still there, but the rest of the bike was a completely different beast.

The bike’s original ‘stovepipe’ spine had been replaced with a much more modern, and better-looking perimeter duplex frame that was now made entirely of flat steel strips that were riveted together to form the bike’s jaunty new shape.

Classic looks that still drop jaws

The new fuel tank was now nested in the frame from above, like a BMW or Zundapp. The rear suspension this time was made rigid instead of sprung, but in front there was now a set of innovative telescopic forks. The handlebars were formed from a wide stamped plate, and the instruments and switches were placed at its centre.

The new 746 cc, 22 hp, four-cylinder cast iron engine was now made in a single block, together with the upper half of the crankcase. The lower part was a light weight aluminium, and housed an internal oil sump.

The removable cast-iron head of the engine enclosed an overhead camshaft, protected by another aluminum cover. The camshaft was driven by a vertical shaft in front of the engine, and an automotive-style distributor was place where it meshed with the camshaft, pointing forward.

The valves were arranged in a v-shape, and were opened by rocker arms that protruded through individual holes in the rocker cover – or ‘cam cover’ as the case may be. Thusly, the rocker-valve pairs were open to the elements, facilitating easy adjustment of their gaps. In a similarly eccentric engineering call, a tube from the carb to the crankcase created a vacuum down below to stop oil leaks.

And in a clever modular (and quite modern) design feature, the factory was able to equip the bike with either a left hand or left foot gear change lever with ease. Customers were spoilt for choice, until they committed to a foot-only gear change lever in etc lat 1930s. The brake lever, as ever, was on the right.

Note car-like distributor positioned at top left of engine, and crankcase ventilation through carb

Then in 1936, the front fork was strengthened, and the wheels were upgraded with reinforced hubs. At 172 kg (380 lbs), the motorcycle could reach speeds of up to 110 kmh (70 mph). In this form, production continued until the late 40s, when the bike’s last upgrade took place. This included a front fork redesign, a repositioned headlamp, and a more compact, enclosed seat suspension system.

Rockers emerge from either side of the covered overhead camshaft

In this form, the motorcycle was produced until 1959, when its production ceased completely, and for another four years spare parts were produced. Amazingly, there are an estimated 4000 Nimbus that are still registered and regularly ridden in Denmark, where spare parts are cheap and easily available. Suddenly, we’re getting the urge to emigrate.

The Nimbus were used both in a single variant and with sidecars. And they were not only sold to private individuals, but were also supplied to the army and police, and even exported abroad in small quantities. In the history of motorcycle construction, the Nimbus remains, perhaps, the only motorcycle that was produced for more than 20 years without any real changes. And by looking at this classic example, it’s not hard to see why.

Nimbus, or Boomerang?

Motorworld by V. Sheyanov – Facebook – Instagram ]








  • John Forsythe

    Very cool.

    What is the nob on top of the steering crown for?

  • Jim Roberts

    it’s like looking at a finely framed portrait of your great grandparents on their wedding day.
    young and strong and beautiful and full of anticipation for the rode ahead. in the picture we can see in the background, the hand-pump at the well, the auto they stand beside has wagon wheels and uses a crank to be started and the chickens in the yard, make us pause and reflect on how far 2017 is removed from that time. with the advantage of modern sensibilities it would be impossible to critique it using criteria we all employ these days when holding forth on the “bike du juor”.that being said, i look at this as a piece of “motorhead tiffany”. it’s an object that has transcended its’ original raison d’etre and whose sole purpose now is to delight the eye. and it’s not just incidental that it causes you to shake your head when you realize just how cool great granny and gramps really were.

    • Hahahaha. Sounds like you’re more than a little inspired, Jim. Great to see!

      • Jim Roberts

        yeah, i’m a sucker for deco rendered in red

    • bill smith

      Ditto, What he said!

  • Got to admit – this bike had us scouring the classifieds. Unfortunately it seems like there’s not too many in Australia…

    • ccc40821

      Currently there are somewhere between 30 and 40 Nimbuses Down Under.

  • tony norskog

    I own and regularly ride a ’54 Nimbus in N. California. It’s one of my favorite and most attention getting classics. It corners better than one would expect, has proven amazingly reliable over the 1800 KM I’ve put on it and was restored in Denmark sold via ebay. They do come up occasionally and trade in the 10-15k range for nice ones.

    • VERY tempted. What do they sound like?

      • Flathead

        Here in Denmark it was nicknamed Humlebien (The Bumblebee) due to its sound.

      • ccc40821

        Humming sound if they’re in good nick – but also often like a car with a bad exhaust.

    • Kaj Pedersen

      Hi Tony, why then don’t you join our Nimbus Club here in the states. I am the founder of the Nimbus club here in the states and I am located in SoCal, owner of 5 of these beauties, including my cherry red 1949 every day rider. Check us out at http://www.nimbusclubusa.com

  • AB

    I’d like to see the custom world take a big block Japanese bike engine and spin it 90 degrees like this.

  • This thing is classy!

    Just signed up for your Newsletter! Nice work!
    Cheers!

  • Henrik Ironhead Elholm

    Got my MC license i 1970 on a Nimbus (live in Copenhagen Denmark)
    Worlds best MC.

    • martin hodgson

      That must be the coolest bike anyone has ever learnt on!!!

  • martin hodgson

    The Motorworld by V. Sheyanov motorcycle collection must be one of the very best and we’ve been so lucky to have so many of their bikes on Pipeburn. It’s bloody incredible what folks were coming up with all those generations ago, each bike has been incredible. But the sheer mechanical majesty of this one, that big four pot mounted longitudinally and creating such a slim profile… it’s bloody perfect!

  • Andy Rappold

    B.E.A.U.T.I.F.U.L!

  • ccc40821

    Very nice presentation of my favourite motorcycle (I own six), though a few corrections are in order:

    * The frame consists mainly of flat steel strips, and they’re riveted together.
    * Only the camshaft gets lubricated, not the valves. Still they go 30K miles between overhauls.
    * Hand and foot gear change was on left hand side only. Brake levers on right hand side only.
    * It started out as hand gear change only. Then some models got the foot gear change, and by late 1930s all were foot gear change.
    * Crank case ventilation was to create a vacuum inside the engine, to prevent oil leaks.
    * There was no oil tank, just a regular sump.
    * There was no export to speak of – less than a dozen of the 12,000 ‘Bumblebees’ built went to customers abroad.
    * Production ceased in 1959.

    For more info the wikipedia entry is a good place to start. And for watching the rocker arms moving, there’s a number of clips on youtube.

    Cheers

    • Thanks for the corrections. In our own defence, the information was translated from Russian via Google, so there was bound to be a few loose ends with the technical details. We’ll update the text where appropriate.

      • ccc40821

        First of all, there’s no need to apologize. I know how much effort goes into maintaining a blog like yours, and the potential for the odd inaccuracies.

        Before writing the correction, I thought for a while about said effort, and the chances you have to get everything right first time around. If you wrote a similar story about – say – an old Husqvarna or Belgian FN, somewhere there’d be a good enthusiasts with a lot more detail knowledge of those bikes. Depending on their enthusiasm (or level of anal-retentivess), they can and often will choose to correct whatever should be corrected. This, of course, can be done more or less diplomatically: “Dear Sir, I’d like to point out…” vs. “You’re a total jerk and I’ll boil your head in 50W engine oil…”

        Writing about rare or unusual motorcycles doesn’t make it easy, and using google.translate to turn a Russian text into proper English probably doesn’t help much either. One way of avoiding mistakes is to run the article by one of those enthusiasts, or let the enthusiast in question write the article, which may or may not be an option for you.

        As for your taste in bikes, well …. it’s your blog, fer chrissakes….