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Motorcycle Investor mag

Falloon on BMW R69S

(by Ian Falloon, Feb 2022)

BMW's conservative R69S was a true mile-eater

Although BMW has produced a variety of single, twin, four and six cylinder motorcycles, it is the boxer twin that has become the BMW trademark. Ever since the first R32 of 1923, the most prized BMWs have been flat twins, and one of the most sought-after is the 600cc R69S.

Produced between 1960 and 1969 the R69S owed its origins to the 500cc R51/3 of 1951. While the R51/3 engine layout was similar to that of the earlier pre-war overhead valve twins there were many improvements. These included a single camshaft driven by helical cut gears instead of the earlier twin camshaft design with its long wear-prone timing chain.

Other developments saw the magneto and generator now housed inside redesigned engine covers but still retained was the pressed-up crankshaft running on roller bearings. However, while the engine featured many improvements the general chassis was carried over from the pre-war models. This included a rudimentary telescopic front fork and dubious plunger rear end.

Considering BMW rose from the ashes at the end of World War II, they were going from strength to strength in the early 1950s. For 1952 a 72x73mm 594cc R67 and a higher performance 35 horsepower R68 joined the R51/3. By late 1953 the 100,000th post-war motorcycle left the rebuilt Munich works.

In 1955 the twins finally received a new chassis, this following the unusual form of the RS54 racer released a year earlier. The running gear now included swingarm suspension front and rear, with the driveshaft incorporated within the rear fork leg. While swingarm rear suspension was now considered mainstream an unusual leading-link Earles fork replaced the usual telescopic front fork. While providing built-in anti-dive under hard braking, the Earles fork was really more suitable for sidecar use, a popular alternative in the 1950s.

These new twins became the 500cc R50 and 600cc R69 but they also coincided with a general downturn in motorcycle sales that saw many Italian and German makes disappear altogether. BMW also narrowly avoided bankruptcy until the success of the BMW 700 car during 1959. Despite the gloomy times updated twin-cylinder motorcycles were released during 1960, one of these being the sporting R69S.

Ostensibly identical to the touring R69, underneath the R69S’s similar exterior was a reworked engine. With a 9.5:1 compression ratio and twin 26mm Bing carburettors the power was 42 horsepower at 7000 rpm. A timed rotary disc engine breather was mounted on the front of the camshaft and a larger air filter and mufflers improved gas flow.

Completing the performance specification was a closer ratio four-speed gearbox and a hydraulic, rather than friction, steering damper.

The chassis was carried over from the R69, with 18-inch alloy rimmed wheels front and rear and a 200mm twin-leading shoe front brake.

Although the R69S weighed a considerable 202kg there were few machines available at that time that could comfortably and reliably cruise at high speed on the German Autobahns. An R69S wasn’t as agile as a comparable British twin, and there were some initial problems if the engine was revved unduly hard. However, after BMW incorporated a vibration damper on the end of the crankshaft from 1963 the R69S would run all day at its maximum speed of around 175 km/h. This was something you couldn’t say about the British competition.

Unfortunately the R69S’s conservatism counted against it during the 1960s. Only available in black with white pin striping (or white or red to special order) they were always expensive and exclusive. Against the good looks and raw power of the British vertical twin the BMW was seen as an anachronism. Instead of a tiny fuel tank and slim seat the R69S offered a 17 or 24-litre tank, small solo saddle or large dual seat.

The only attempt at modernisation was the alternative of new long-travel telescopic forks for the US market in 1967. However, these were not popular and eschewed by the traditional BMW buyer in favour of the traditional Earles fork version. By 1969 the market required a new machine, and economics dictated that the R69S engine, with its built-up crankshaft and gear-driven camshaft, be replaced by one more suitable for mass production.

With over 11,000 produced between 1960 and 1969 the R69S may not be a limited production machine, but it is still representative of that earlier era when the accountants didn’t rule the engineers.

As a motorcycle possessing all those usual BMW qualities of comfort and longevity, the R69S provided the best of both worlds. An eminently practical and useable classic motorcycle, the R69S has justifiably earned a place as one of the most desirable post-war BMW motorcycles.

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BMW R69