The R50/5 was presented with the entire 5 series at the end of August 1969. This new range consisted of the R50/5, the R60/5 and the top of the range R75/5. These new models were equipped with a completely new engine. This engine was designed in 750, then declined in lower displacements by reducing the bore. The crankshaft was forged in one piece unlike the stamped one of the R50/2, and it turned on plain bearings. The connecting rods were now removable. The camshaft was now placed under the crankshaft and driven by a Duplex chain. At the rear of the camshaft was the new Eaton type oil pump allowing the fitting of plain bearings. The cylinders were made of light alloy and advantageously replaced the cast iron cylinders of the R50/2. The carburetors are still slide carburetors for the R50/5 and the R60/5 and vacuum carburetors (BING CV 64/32/3-4) for the R75/5. Above the engine block is a starter, optional on this 500cm3 model. The kick is of course still present to reassure the skeptics. The gearbox is still 4-speed but the ratios and selection are improved compared to the R50/2.
On the chassis side, there are also major changes. A new double cradle frame inspired by the Norton "featherbed" frame. The Earles fork is abandoned in favor of a hydraulic telescopic fork, an improved model of the R50 US. The rear part abandons the frame loop system for a more conventional swinging suspension system at the upper shock absorber attachments. Plastic also makes its appearance for the mudguard. The tank remains made of sheet metal. The R50/5 is available in a range of colors which breaks with the R50/2 which was available in black or an optional white.
For the 1971 model year, a turn signal indicator appears on the dashboard.
It was not until the end of 1972 that the 5 series underwent more significant modifications. The swingarm was extended by 5 cm to, on the one hand, reduce the steering and on the other hand, allow the installation of a larger capacity battery for the electric starter (optional for this model). The flywheel was lightened to improve revving, the rear rim was widened (WM2 to WM3), the side stand was equipped with an automatic folding system and the tank was now 17 liters with chrome sides, the 24 liter tank with knee grip remained available as an option.
Production of the R50/5 was stopped at the end of 1973 after 7865 units. With the discontinuation of the R50/5, the 500cc displacement in the BMW range also ends, as the entry level of the new 6 Series is represented by the R60/6.