BMW R 75/5
| BMW | |
|---|---|
 R 75/5 model year 1973 |
|
| R 75/5 | |
| Manufacturer | BMW motorcycle |
| Sales description | R 75/5 |
| Production period | 1969 to 1973 |
| class | motorcycle |
| design type | Sports Tourer |
| Motor data | |
| air-cooled two-cylinder four-stroke cycle - boxer engine , mounted longitudinally | |
| Displacement (cm³) | 749 |
| Power (kW / PS ) | 37/50 hp at 6200 min -1 |
| Top speed ( km / h) | 175 |
| transmission | 4 courses |
| drive | Cardan drive |
| Brakes | Drum brakes |
| Previous model | R 75/4 |
| successor | R 75/6 |
The R 75/5 is one of BMW produced motorcycle with an air-cooled two-cylinder four-stroke - boxer engine , which was manufactured from 1969 to 1973. It is the top model of the so-called "dash-five" series, which consists of the models R 75/5 (750 cm³, 37 kW / 50 PS), R 60/5 (600 cm³, 30 kW / 40 PS) and the R 50/5 (500 cm³, 24 kW / 32 PS) consists. With a comparatively low specific power, they were designed for pulling power and durability.
history
With the R 75/5, BMW responded to the new demand for sports motorcycles after sales of the outdated swing arm models had almost come to a standstill.
The R 75/5 was replaced by the R 75/6 and the R 60/5 by the R 60/6 . The 500 model did not have a successor. The successor series offered two larger displacement 900 models above the 750 engine, the R 90/6 with 60 hp and the R 90 S with 67 hp.
technology
The series replaced the “ full swing BMW ” built from 1955 onwards. It was not just a model upgrade, but was completely redeveloped. The frame was modeled on the Norton duvet frame. The engines were also new designs with plain bearings on the crankshaft instead of the roller bearings of their predecessors.
The top-of-the-line R 75/5 was also the first BMW with Bing constant pressure carburetors , which had been on SU British engines since the 1950s. The direct actuation of large slide cross-sections with a Bowden cable was disadvantageous, especially with large-volume engines. It led to the "swallowing" and collapse of the fuel atomization when accelerating quickly. So a throttle valve was built into each carburetor, the slide was operated by a diaphragm to which the difference between the intake pipe and external pressure was applied. This construction principle had long been common in automotive engineering.
The models received the duplex drum brake in the front wheel, which was common at the time. Disc brakes were only available with the introduction of the / 6 models from the end of 1973. A full-hub simplex brake was mounted on the rear wheel. All models have a four-speed gearbox and cardan drive to the rear wheel. For the first time, the engines were equipped with an electric starter together with the kick starter (on request for the R 50/5). The frames were no longer suitable for sidecars . At that time, the equipping of motorcycles with H4 headlights, which was available from 1972, was not very common. The models were revised several times during the production period. The biggest change came shortly before the end of production in 1973, when the rear swing arm and thus the entire rear end was lengthened in order to stabilize straight-line stability when driving fast on the motorway (long swing arm). This was carried over to the successor R 75/6 . The additional space gained could be used for a more powerful starter battery from the / 6 series.
Instead of the traditional line of the 1950s with the horizontally positioned silencers and black paintwork, color schemes were offered for the first time. The tank was available in three different versions. The original version had a large, somewhat angular-looking 24-liter tank. The small 17-liter version that replaced this first version in 1971 was also available for export with chrome-plated side caps. The large 24-liter tank was only available at an additional cost from 1971. In 1973 the chrome version was dropped again, but the smaller tank was retained.
Technical specifications
.JPG)
| Parameter | R 50/5 | R 60/5 | R 75/5 |
|---|---|---|---|
| drilling | 67 mm | 73.5 mm | 82 mm |
| Hub | 70.6 mm | ||
| Displacement | 498 cc | 599 cc | 749 cc |
| power | 32 hp (24 kW ) at 6400 min -1 | 40 hp (29 kW ) at 6400 min -1 | 50 hp (37 kW ) at 6200 min -1 |
| Top speed | 157 km / h | 167 km / h | 175 km / h |
| Empty weight with fuel | 205 kg | 210 kg | 210 kg |
| Perm. total weight | 398 kg | ||
| Tank capacity | 17 or 24 liters | ||
literature
- Hans-Jürgen Schneider: BMW R 45 - R 100 RS from year of construction 1976. BLV Auto- und Motorradpraxis, Munich / Vienna / Zurich 1984, ISBN 3-405-12908-7 .
- Don Morley, Mick Woollett: BMW. Heel Verlag, Königswinter 1994, ISBN 3-89365-402-X .
- Endurance test BMW R 75/5 over 10,000 km. In: The motorcycle . Issue 4/73 of February 24, 1973, Motor-Presse-Verlag, Stuttgart.
- The motorcycle. Issue 20/73 of October 6, 1973, Motor-Presse-Verlag, Stuttgart.
- Hans-Joachim Mai: 1000 tricks for fast BMWs. 12th edition. Motorbuch-Verlag, Stuttgart 1991, ISBN 3-613-01117-4 .
- Manfred Nabinger: BMW motorcycles from ninety years. Podszun, Brilon 2012, ISBN 978-3-86133-638-9 .
See also
Web links
- BMW R 75/5. In: BMW history. BMW AG, accessed on November 18, 2019 (dossier in the BMW Group Archive).
- Repair manual BMW R50 / 5 R60 / 5 R75 / 5. (PDF) In: BMW history. BMW AG, September 1969, accessed on November 20, 2019 (repair instructions with pictures and technical tables, 189 pages).
Individual evidence
- ↑ Operating instructions motorcycles R50 / 5 R60 / 5 R75 / 5. (PDF) In: BMW history. BMW AG, August 1969, accessed on November 21, 2019 (owner's manual with pictures and technical tables, 83 pages): "[...] the motorcycle is a permanent challenge for men [...]"
