This 1954 BMW R25/3 has been restored some years ago and runs well.BMW’s first new post-war model was a single-cylinder design – the 250cc R24 – which arrived in 1948 looking pretty much like the pre-war R23 but producing an additional 2bhp. It was superseded in 1950 by the R25, which featured plunger rear suspension but was otherwise very similar.
An improved R25/2 version was introduced during 1951 incorporating a stronger crankshaft and minor revisions to the front mudguard stays and seat springing. Built between 1953 and 1956, the final R25 variant – R25/3 – featured a new telescopic front fork, full-width alloy hubs and alloy wheel rims as the principal upgrades.
The engine of the R 25/3 produced 13 hp. It had a long-stroke, hydraulically damped telescopic fork and was the first series-produced BMW motorcycle to have full hub brakes. At the rear, the straight-travel suspension was retained, in contrast to the swingarms of the later models released from 1955.
Like the previous model, the BMW R 25/2, the BMW R 25/3 is powered by a longitudinally installed single-cylinder four-stroke engine. The multi-part, pressed crankshaft has three roller bearings in the engine housing, the non-divisible connecting rod has roller bearings on the crank pin. A side camshaft controls the valves via tappets , bumpers and rocker arms.