Surface treatment

The 1934 Nimbuses we see nowadays have all suffered, to some degree, from ageing. They might be a bit rusty. Or they have been painted over, or have undergone a total restoration and have been provided with new paintwork, chrome and nickel. 
Therefore, it can be very difficult to know what kind of surface treatment a 1934 Nimbus originally had. We can collect some information from sales brochures, drawings, and old parts, but we will never be totally sure about all details.

The following is a best guess; I only included those details, which I’m pretty sure of.

 

Paint work

All painted parts of a commercial 1934 Nimbus are black (RAL-9005), with the exception of the bottom part of the tank, on which a silver coloured paint is applied (original stove enamelling which is no longer applied).
The kick starter and clutch and brake levers, which are cadmium plated for later models, were painted black for the 1934 model. Some advertisement posters indicate that this could also the case for foot rests, the brake pedal and the clutch pedal.

Postal Service machines are yellow (Danish Postal Services yellow). Those of the army were green (Army standard green).

 

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Nickel plating

Nickel plating was widely used as a surface treatment for motorcycle parts in the thirties and the Nimbus was not an exception. Many parts, which are cadmium plated on the newer models, were nickel plated on the 1934 motorcycles. 
The list below is mainly based upon the observations of original, un-restored spare parts from 1934.

The parts below are nickel plated.

flange on the oil filter

inner telescopic pipe (lower 15 cm)

valve spring

clamp for sleeve

upper and lower spring cups

ignition shield

horseshoe shaped valve cotters 

bolts for hand grips

heat shield

push button for horn

ignition housing

brace for speedometer

brace for ignition coil

lamp bush (fitting)

brace for spark plug cables

bush for speedometer drive

clamp for dynamo

headlamp ring

petrol line

pivot and nut for brake light switch

suction line for lubricating oil pump

slotted bolts 

lube oil return line for camshaft housing

 

 


Chrome plating

Chrome plating was also used on the 1934 model. Chrome plating was carried out using the original and foremost method by incorporating a copper layer as a base. This is a relatively expensive surface treatment and was therefore only applied on those parts which were exposed to wear or weather conditions.

The following parts were chrome plated:

Choke valve for carburettor         

clamps for fuel tank

Cover plate for carburettor intake

gear lever

Cover for throttle valve

tension bolt for steering damper

Exhaust pipe (most of them are however stove enamelled)

rear seat hand grip

Head light ring

drive shaft

 

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Cadmium plating

Cadmium plating is a sound and sustainable surface treatment, widely applied by A/S Fisker & Nielsen, for small parts such as nuts and bolts. Many parts which were nickel plated for the 1934 models were cadmium plated for later models.

Unfortunately cadmium is a toxic heavy metal, therefore cadmium plating is no longer carried out.

 

Burnishing

For the first 1934 models, rockers, rocker guides and the cover plate on the back of the camshaft housing were presumably left untreated. This changed at the end of 1934 to black burnishing.

 

Untreated

 It would appear that currently (1996), all bolts were untreated, but a thin surface treatment may have worn away over the years.

 

 

 

 

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