Wednesday, March 31, 2010

BMW RS 54








This was taken from the discription of bike offered for sale at http://www.classic-motorbikes.com/. I have not been able to locate some of this information at any other place, but either way a great machine.



One of the most mythical competition bikes of the 50s, the fabulous BMW 500 Rennsport.The here presented bike is exceptional in several points: This is not only likely to be one of the very rare works type 256 with only 8 examples ever produced, but on top of it this one is in an exceptional running condition. It is frequently ridden by its owner during classic bike events.
In the 50s, the BMW factory produced 25 RS 54 type 253 and 8 type 256. The works type 256 shows the following differences to the privateer RS 54 type 253:* Oversquare engine (70 x 64.5),* Dell’Orto 37 mm carburettors with separate float chambers,* Double ignition (4 spark plugs),*

Earles forks with a straight rear section (instead of bended),* 5 speed transmission,* transmission shaft parallel to the swing arm,* hydraulic rear brakes,* front mud-guard fixed on the frame.
The exact history and palmarès of this bike are unknown. The famous rider Walter Zeller, official BMW racer from 1951 to 1956, rode the type 256 with success:German Champion 500 in 1951, 54 and 55.Vice World Champion 500 in 1956 behind John Surtess and the MV.Walter Zeller stopped competition beginning 1957. He participated in historic races in Europe from 1979 to 1988 with his loyal mechanic Gustl Lachermeier, who accompanied him throughout his career at the BMW race department.Gustl restored and prepared two marvellous bikes: a 1946 RS Kompressor and a Rennsport type 256 a with an oversquare engine from 1968.Following the owner of this Rennsport, it was also Gustl Lachermeier, who restored this bike in the 80s and it was used by Walter Zeller in historic races.
This extremely rare bike is available in Germany.

Following the book “Les BMW Rennsport” by the French Marc Muylaert, Walter Zeller used a works type 256 in the years 1954 and 1955.That type 256 had forks with straight tubes, and not curved ones like the 253. The transmission shaft wasn’t located in the tube of the swing arm but parallel, so that the reactions at braking and acceleration no longer pass by the swing arm itself, but by a long parallel rod supported by the frame. The rear mud-guard of the 256 was suspended on the frame, and not directly on the swing arm, where it would increase the weight of not suspended masses. Last but not least, the 256 was streamlined, which slightly increased its top speed.Regarding the engine, although it had many parts in common with the privateer bikes, the one of the type 256 can be distinguished by its measures, the larger valves, its cam shaft, the rocker arms and the air intake accepting Dell’Orto 37mm carburettors. The power was approximately 60 HP, which means about ten more than the 253.

The Technical Characteristics
Engine
flat twin air cooled, DOHC
Capacity
494 cm3
Bore x stroke
70 x 64.5mm
Carburettors
2 Dell’Orto 37 mm with separate float chambers
Gearbox
5 speed
Clutch
Diaphragm, Titan fly wheel
Weight
138 kg
Tank
24 l
Length
2030 mm
Width
670 mm
Wheel base
1370 mm
Heights of seat
700 mm
Top speed
225 km/h
Power
65 HP at 9000 rpm
transmission is a 5 speed (4 speed on the 253).