Frame, Seat, Exhaust pipe, etc.

Frame

The 1934 frame can be recognised initially by the relatively thin head tube which has, at the lower end, a flat steel bar reinforcement welded onto it. The head tube is connected to the frame by means of wings, welded onto the front and riveted to the frame. The very first frames did not have a head tube with the welded flat steel-bar reinforcement. Even with the flat steel-bar reinforcement, the head tube was still much too weak for daily use, consequently, from frame number 1550 a stronger head tube was produced which was reinforced with extensions at both sides, forming a cap around the head tube.
Many of the1934 frames that still exist today, at some point have experienced a fractured head tube and therefore F&N fitted the new, stronger head tubes

The frame plate behind the tank has a cut away for the gear lever. In addition, there are two threaded holes for the clamp to fasten the tank, and two holes for the frame number plate and the brace for the electrical wiring.

A threaded 8 mm hole for fastening the heat shield is located on the righthand side between the foremost rivets of this frame plate.

 62.

Head tube with reinforcement

The reinforcing plates for the rear wheels are attached to the frame by means of rivets with a spherical head; in 1935 the rivets were countersunk on the inside.  The space between the two plates is filled at the front by welding in a piece of flat bar.
The plate at the left side has a single hole for the attachment of the cover of the crown wheel.

The rear mudguard has a small hole for the rigid drive shaft and a shelf for the battery riveted onto it.

The first machines of 1934 were not equipped with a stop light switch and therefore the rear mud guard did not have holes on the right hand side for the wiring and the stop light switch. These holes were drilled later when the stop light switch was fitted.
It is noticeable that these holes were drilled later, partly because of varying positions and partly because the hole for the wiring is not provided with the later trumpet shaped hole to protect the wire.

Starting with number 1400, holes were provided for the wires and the stop light switch on the right side of the rear mud guard.

 63.

Frame, details of the rear wheel

The flat steel of the frame, the seat support and the reinforcement of the mud guards are oftenmarked “FAGERSTA”, “0,35” and a swastika. “FAGERSTA” is the name of the Swedish steel company, “0,35” refers to the steel quality which is hardened and tempered with a carbon content of 0.35%. The swastika was the company’s logo at that time.

64.

       66.

[Translation of page 66]

[Photograph]

Why should you buy a MOTORCYCLE?

Good question, why should you buy a pedal-bicycle? The same reason why the bicycle has become the national means of transportation in Denmark is equally valid for the MOTORCYCLE, the difference being that cycling is hard work in a head wind and when climbing hills, it is slow and has a limited range, whereas the motorcycle is comfortable, fast and has no limitations with respect to distance. With one’s Nimbus, one swishes away in the fresh air, unbound by time schedules or railways. One can visit all kinds of remote places outside the usual scenic routes. One can bathe at lonely beaches, far away from overcrowded and dirty beaches; one is, in short, one’s own boss. One has the same operating range as a car, but at much lower cost. And no road is too narrow for a motorcycle. For workers who have to travel a long distance to their work, the motorcycle is the most comfortable and economical means of transportation, provided you purchase the most economic machine, - a Nimbus.

[Photograph]

Every child in the country knows

NIMBUS.

The vintage models of Denmark’s most popular motorcycle are still in the ownership of numerous customers, who, before production ceased in 1927, bought themselves one of these long lasting machines.
One cannot ask for a better recommendation of the indisputable quality of our product, and because the new Nimbus is built on the same principles, taking into account the choice of materials, practical design and operating principles. We suggest that you won’t go wrong with your selection.

Nimbus -

Denmark’s motorcycle.

 66.

[End of translation of page 66]

Two people, like it should be

See Denmark from a Nimbus.

 67.

[Translation of page 68]

 [Photograph]

Danish engineering works

When the high demand for our Nilfisk vacuum cleaners, from both abroad and at home, forced us to temporarily cease production of the Nimbus, it has constantly been in our thoughts and the model, which we have put on the market now is the result of, not only our earlier years of experience, but also of many years of research and development, such as the critical judgement of the industry developments which have taken place in this field. So the construction of the new Nimbus combines the best of the old one with the improvements made during the intermediate years. Therefore the New Nimbus has become the ideal motorcycle.
All technical details and benefits are listed in the specification on the next page, but if we want to emphasise one thing, it would be the simplification of the design such as using the dynamo for the transmission between crankshaft and overhead camshaft. 
Naturally, the four cylinders and shaft drive remained, because all motorcycle riders prefer the smooth, vibration free 4 cylinder engine and they prefer the shaft drive over a chain or belt drive, which everyone has problems with. 
But other construction aspects underwent fundamental improvements, for example the cylinders, which together with the upper part of the crankcase were cast in one piece into the block, combining strength, ease of cleaning and improved cooling and protection

[Photograph]

NIMBUS

DENMARK’S MOTORCYCLE

68.

[End of translation of page 68]

 RESULT OF 15 YEARS OF EXPERIENCE

 69.

[Translation of page 69]

against incorrect assembly after possible repairs, than with four separate cylinders.
The crown- and pinion wheels of the shaft drive are provided with chamfered teeth, resulting in quieter running and improved resistance against wear and tear.
The only moving parts of the engine exterior are the valves and rockers fitted on both sides of the camshaft housing. One will not find long push rods on the engine’s exterior; all vital parts are enclosed and protected against dust, rain and damage.
The new Nimbus has a higher compression ratio, resulting in increased power with the same cubic capacity as the old one, 746 cm³. Therefore one will not find a finer motorcycle for sidecar use on Danish roads, strong enough to negotiate every hill in the country in third gear with 3 passengers whilst providing efficient fuel consumption.
The Nimbus is assembled in Denmark with ALL parts produced in the country resulting in cost effective spares and minimal delivery times over
The rider will always deal with the factory itself or with its authorised dealers. Nimbus has a network of service stations throughout the whole country where specially trained mechanics can provide our customers with the best possible service.
In short, the best motorcycle for use in Denmark

[Photograph]

Danish invention

[Photograph]

RESULT OF 15 YEARS OF EXPERIENCE

 69.

[End of translation of page 69]

[Translation of page 70]

The Nimbus engine

[Clockwise]

Engine.
Four Cylinders with overhead valves and overhead camshaft. Compression ratio 1:5, Bore 60 mm, Stroke 66 mm, Cubic capacity 746 cm³, Power output appr. 18 hp.

Pistons are made of alloy, with three piston rings at the top and one oil control ring at the bottom.The gudgeon pins are fully floating.

The connecting rods are drop forged. The small end bearing is made of phosphor bronze and is lubricated under pressure through the bore in the connecting rod. The big end bearing is made of white metal.

Ball bearings

The crankshaft is very heavy and forged in one piece. It has a unique design for the lubrication of the big end bearings. The crankshaft rotates in two heavy duty ball bearings.

In order to drain the oil, the lube oil suction pipe is provided with an easily detachable lube oil filter.

The lube oil pump is bolted directly to the cylinder block and is driven by the vertical shaft of the dynamo. It is a gear pump of simple, robust construction.

The lube oil is fed under pressure to the crankshaft. Oil is also pumped via a pipe to lubricate the camshaft bearings, cams and rockers. Another pressure line feeds the oil to the gearbox.  

The dynamo is placed vertically and is directly fitted to the cylinder block. It supplies electricity to the battery, the lights and the ignition.

The valves are placed at an angle in exchangeable guides and have two springs per valve. The valves are easily adjusted. The inlet valves are lubricated automatically via the carburettor. 

The overhead camshaft is fully enclosed in a  dust proof housing, located on top of the cylinder block. The shaft runs in two bronze bearings, lubricated under pressure, and is driven from the crankshaft through the dynamo shaft by means of bevel gears.

The rockers are fitted in the camshaft housing and transmits the movement of the camshaft to the valves.

[bottom part of the page]

The  transmission of power to the rear wheel takes place by means of the drive shaft to the dust proof gear housing in which the drive pinion runs. The crown wheel is fitted with a special thrust bearing, tightened with bolts to the rear wheel hub.  The teeth are bevelled. The frame is double sided using special profile steel, which gives increased strength. The stand is located in the centre. The rear mudguard is wide and is hinged to assist in removal of the rear wheel. The front mudguard has closed sides (valances).
The telescopic front forks are simple, yet strong and give a damping action. Two long enclosed coil springs provide an effective spring action.
Fuel tank. 12½ litre capacity, with a 2 litre reserve via a separate reserve tap. 
Seat. Seat height is low, about 700 mm. The saddle is wide and excellently sprung. The foot rests are adjustable and fitted with heavy rubbers.
Wheels. The wheel base is approximately 1400 mm. The wheels are easily removed  and have 26” x 3½” high quality heavy duty rubber tyres.
Brakes. Both wheels are fitted with independently operated, self-adjusting drum brakes, resulting in more effective braking. The rear brake is controlled by the right foot pedal, the front brake with the right hand lever.
The handlebars are made of pressed steel. The indirectly illuminated ammeter and speedometer are located in the middle of the handle bars. The handle bars are provided with two levers for front brake and clutch, plus two twist grips.  The right twist grip controls the throttle, the left one the lighting. In addition, the horn and horn switch are fitted on the handle bars, as well as the switch for ignition and lights. 
Battery. The high quality battery is located under the saddle and is adequately protected. All wiring is insulated and protected.
The tool box is fitted behind the engine and is easily accessible. A comprehensive set of tools is included.
Weight. Incl. all accessories and rear seat 170 kg.

70.

[End of translation of page 70]

[Translation of page 71]

The Nimbus engine

[Anti clockwise]

The battery ignition unit is fitted in line with the camshaft and enables automatic timing. H.T. leads are fitted with protective caps and they connect to 14 mm spark plugs.

The carburettor is automatic with adjustable nozzles and an acceleration pump. A pipe is fitted between the crankcase and the carburettor to extract hazardous fumes from the crankcase whilst maintaining a slight vacuum in the crankcase, thus preventing oil from leaking out between the joints.

The cylinder block. The 4 cylinder block is cast in one piece, with large, cooling fins. The top section of the crankcase housing is also cast in one piece. 

Dipstick.

The base of the crankcase housing is cast of aluminium, has cooling fins and contains 2½ litre of oil.

Crankcase ventilation.

The kickstarter is located at the left side of the machine and meshes directly with the crankshaft.

Flywheel.

The clutch is a single, dry plate clutch, suitably sized and placed in the flywheel. Declutching takes place by means of a special thrust bearing. The clutch is operated by the left foot pedal or the left hand lever.

The 3 speed gearbox is bolted directly to the engine, with ratios to the rear wheel of 4:1, 6.1:1, and 9.7:1. All bearings are sturdy and are lubricated automatically.

Gearshift.

The cylinder head is cast in one piece, together with the inlet manifold and both have large cooling fins. It can easily be taken apart. The compression chambers are spherical, this being the ideal shape.

Standard sidecar

[Photograph]

The windscreen is adjustable and also serves as a cover

71.

[End of translation of page 71]

[Translation of page 72] 

[Photograph]

A quality machine

The illustration shows:

One of the new Nimbuses used by the Danish Postal Services. No better proof of quality and durability can be portrayed than with the Nimbus motorcycles of the Postal Services.
Day in, day out, they are ridden in streets and on roads in all kinds of weather. Delays are unacceptable.
The oldest Postal Services machines are now 15 years old and their service irreproachable. – When a Nimbus is maintained correctly, it will last forever.
The Nimbus is also used within many other Danish Public Services, such as the  State Police, Copenhagen Police, Electricity Services, Traffic Police, Telephone Companies and for transportation of goods at numerous private enterprises. Upon request we can offer a maintenance contract for larger clients, for a fixed price per kilometre.

Service and warranty
Service. Throughout the country we have arranged authorised workshops with our authorised dealers, who are more than capable of serving the Nimbus owners in a fully reassuring way.

Maintenance and tuning. three free service checks in the first 12 months, after 300 km, 1000 km, and 2000 km.
These checks include: Valve adjustment. Oil change. Lubrication (oil and grease at owner’s expense) re-tightening fasteners. Lighting and horn check. Battery top up and check of electrical leads. Charging current of the dynamo is measured. Brakes and clutch check and adjustment. Dynamo’s carbon brushes check (only at the 3rd check). Spark plugs check. Carburettor check. Test run.

Warranty. The warranty for a Nimbus is the same as for a car; a certificate of warranty and service card is included with every new machine.

Manufactured by
A/S Fisker & Nielsen
Copenhagen F.

*
Authorised dealer:
C.V.Hansen
Frederiksberg Bredegade 17
Teleph.: Gothaab 6538

DYBTRYK

FRÆNKEL

KØHVN    C8869

…………………………………………………………………………………………………..

Offer coupon

1. The undersigned requests without commitment, a quotation for A new Nimbus.
2. The undersigned requests without commitment, a quotation for his old machine.

Make____________________________ Year_____________________________

Name and profession__________________________________________________

Place of residence_____________________________________________________

Please send to A/S Fisker & Nielsen · Copenhagen · Telephone 9650

 72.

[Translation of page 72]

Seat

The front seat is fitted inside the frame with bolts at the front and bushes  immediately behind the frame plate near the tank, and at the rear with 5 mm or 5.5 mm coil springs. The springs have vertical eyes at both sides and are bolted directly to the frame and to the seat support. The front seat spring brace has 6 mm holes for holding the springs. The rear brace has 4 mm holes. 

Seat and passenger seat, please note that the supports for the rear seat run inside the frame.

Passenger seat

The passenger seat is the same width as the front seat and is similar in shape. The flat steel seat supports hinge around the shoulders in the beads of the hinges of the rear mudguard and hence are fitted on the inside of the frame. The handgrip is a flat steel brace, fitted on the distance piece of the seat supports which is made of 12 mm round steel bar. The holes in the seat supports are drilled at the rear in the side supports of the seat, in similar fashion as the front seat. The front seat spring brace is riveted at both sides to the seat support, the rivets having a spherical head.

73.

The 1934 passenger seat is of poor design and construction. The seat is unstable and the handgrip is uncomfortable to hold. The construction was modified towards the end of 1934 or at the beginning of 1935.

The new seat is wider than the old one. The side members of the seat run on the outside of the frame and are reinforced with two flat steel bars crosswise. The holes for the seat springs have been moved about 40 mm forward. The handgrip is chrome plated round steel tube.
Because the side members of the seat now run on the outside of the frame, the beads on the hinges of the mudguard are no longer useful, but remained during the entire production period. 

Seat upholstery

The upholstery of the seat, or seat cover as it is called nowadays, is made of synthetic leather. The fastening straps of the cover are secured with visible rivets.

 Exhaust pipe

The exhaust pipe is a black enamelled iron pipe with a flattened fish tail. The exhaust probably had no silencer, as F&N’s silencer drawings are dated 1/31/1935.

The exhaust could be ordered chrome plated, which appears in various advertising pictures.

The tail pipe is just a bit too short, resulting in the exhaust gases fouling the rear wheel.  From around number 4500, the tail pipe was lengthened, so that it terminates behind the rear wheel.

74.

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