Retrospective: BMW /5 Series – 1970-1973

1972 BMW R 75/5 slash five toaster
1972 BMW R 75/5 “Toaster” owned by Arden White in Snohomish, Washington. (Photos by Arden White and Moshe K. Levy)

The year 1969 was a tumultuous time in the motorcycle industry, marked by the rise of the Japanese and the beginning of the end for the British. Amidst this backdrop of rapidly evolving consumer sentiment, BMW introduced its /5 (“slash five”) Series for the 1970 model year. In its three years of production, the /5 family of motorcycles reinvigorated the brand with its contemporary design and ushered in BMW’s fabled “Airhead” Type 247 Boxer Twin engine, variations of which would continue to propel the marque’s R-Series motorcycles for the next 25 years.

See more of Rider‘s Retrospective motorcycle stories here.

The /5 Series, built at BMW’s newest facility in Spandau, Berlin, was available in three variants. The R 50/5 (500cc) was the most affordable, the R 60/5 (600cc) was the midrange, and the R 75/5 (750cc) was the top of the line.

Compared to its predecessor, the BMW /2 Series, the /5 Series was a thoroughly modernized ground-up redesign. It boasted up-to-date 12-volt DC electrics complete with a 180-watt alternator, an electric starter, more powerful drum brakes, and a slew of other noteworthy upgrades. The frame was of tubular steel construction with a double downward cradle for the engine, similar to the benchmark Norton Featherbed. A rear subframe was bolted onto the mainframe and served as the upper mount for the twin rear shocks. Up front, the former /2’s Earles fork was replaced with a telescopic fork on the /5, signaling a functional change of focus from utilitarian sidecar duty to improved handling as a solo motorcycle.

BMW 247 Airhead flat-Twin R 75/5
The 247 Airhead’s flat-Twin configuration means easy access to most serviceable components.

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Of course, no discussion of the BMW /5 would be complete without an examination of the Type 247 “Airhead” flat-Twin engine. Special care was taken by the company to design a simple, reliable motor that addressed previous concerns about the /2 mill. To this end, the 247’s chain-driven camshaft runs below the crankshaft, allowing gravity assist of oil delivery to the camshaft and eliminating the periodic complete teardowns required to maintain the former /2 design’s “oil slingers.” Two valves in each hemispherical cylinder head are actuated by the camshaft through followers, pushrods, and rocker arms. A stroke of 70.6mm is constant within the /5 line, with bores of 67mm, 73.5mm, and 82mm determining the displacement of the R 50/5, R 60/5, and R 75/5 respectively.

The R 50/5 and R 60/5 models are equipped with 26mm Bing slide carburetors, while the R 75/5 features 32mm Bing CV units. On all models, the engine power is transmitted via a single-disc dry clutch to a stout 4-speed gearbox and then to the swingarm-mounted final drive via shaft.

1971 BMW R 60/5 slash five
The author’s wife on her first bike, a 1971 R 60/5 with standard 6.3-gal. tank. Now with almost 100,000 miles, it’s still going strong.

For late 1973 models, BMW lengthened the rear swingarm by approximately 2 inches, resulting in the so-called “Long Wheelbase” /5. The tell-tale signs of a Long Wheelbase model are the weld marks on the final-drive side of the swingarm where the extension was added by the factory. The extra room allowed a larger battery to be located behind the engine and gave riders some additional clearance between their shins and the carburetors. To this day, /5 enthusiasts viciously argue over whether the sharper handling merits of the original short-wheelbase models trump the high-speed stability of the long-wheelbase versions.

Either way, at barely over 460 lb, the R 75/5 was one of the lightest 750cc bikes of the era, and with a top speed of 109 mph, it was one of the fastest as well.

1970 BMW R 60/5 slash five
Fred Tausch’s 1970 R 60/5, circa 2004. Today it resides at Bob’s BMW Museum in Jessup, Maryland.

Complementing these functional upgrades to its new motorcycle line, the /5’s aesthetics were also a spicy departure from the more somber BMWs of yore. Although initially available only in the white, black, or silver colors for 1970-71, the 1972-73 models were available in seven hues, including Monza Blue and Granada Red. Further shocking traditionalists, 1972 saw the introduction of the 4-gallon “Toaster” gas tank, which featured prominent chrome accent panels on each side. Though excessive chrome on a BMW was heresy at the time, today the Toaster-tank /5 is considered valuable to collectors, as it was only produced for the 1972-73 model years.

Contrary to the initial worries from BMW traditionalists that the company had strayed too far from its function-over-form roots, the /5 motorcycle family has earned a sterling reputation for anvil-like reliability. Being classic European motorcycles, the /5s naturally have certain idiosyncrasies, but overall, the design and construction are robust. In a testament to their supreme quality, these motorcycles are still often used as daily runners 50-plus years after their initial production.

Experienced owners claim that with timely maintenance, these bikes are nearly indestructible. In fact, properly running /5s with well over 100,000 miles on them are commonplace at BMW rallies worldwide. I met an owner of one, the late Fred Tausch, at a rally in 2004. Tausch’s 1970 R 60/5 had more than 600,000 miles on its clock and was still running when its owner passed away. Details are sketchy, but supposedly the engine was only overhauled twice during this remarkable service run.

The classic BMW motorcycle community is an active one, with abundant technical support and a well-organized network of enthusiasts (aka “Airheads”) who gather regularly to celebrate their favorite machines. Parts are still plentiful, though they’re getting more expensive as time goes on.

Ultimately, the /5 Series represented an initially dramatic but ultimately triumphant gamble for BMW. These motorcycles were not the cautious evolutions of the existing /2 designs that the brand’s faithful fans had expected. The /5’s newfound emphasis on performance and style, combined with significant price increases over the /2 Series it replaced, could have easily spelled marketplace doom. Luckily, that was not the case, and the /5s became a mild hit.

To hear more from Moshe K. Levy, the author of this article, check out Rider Magazine Insider Podcast episode 44


  1. I had a ’74 R90/6 a few years ago, so almost a /5. Of the updates that made it a new model, the extra displacement was probably the biggest. The new front disc for ’74 was famously unimpressive–and weird: the lever pulled on a cable that operated the master cylinder under the gas tank. The new 5 speed had the same top gear as the 4 speed, and the ’74 gearbox had a bad reputation for reliability. Of course, my bike having been over 40 years old when I bought it, I couldn’t say whether it had the original gearbox. (Still, why did a clean-sheet-of-paper design in 1969 get a 4 speed?) Of all the bikes I’ve sold, that one is probably my biggest regret.

  2. I set out to buy an advertised canoe in the DC suburbs. When I arrived, I looked at the canoe and then the toaster-tank R60/5. I bought the bike. My spouse was not amused, but I put 10k miles on it riding to the office.

    I replaced the toaster tank with a “touring” tank. There was a lot wrong with the bike, but it ran and ran. loose connecting rod bearings top and bottom, well worn valve guides – it had top and bottom spark plugs I suppose because the bottom ones tended to foul.

    but with all that it never let me down once. I loved it. Then we moved to Miami and I sold it in DC.

  3. I was the proud owner of a 1972 R75/5. Wife and I averaged 12,000 miles a year on weekends and vacations with no problems. Being based in Denver we covered Colorado, Wyoming, Utah, New Mexico and Arizona–Canada to the North, Nebraska to the East, Texas to the South and California to the West. My Beemer was equipped with a Vetter fairing, BMW hard side bags and a rack that carried two stuffed bags with camping gear. The greatest time of my life– and the saddest time when I had to sell it do to work requirements.

  4. I have a 1993 R100R. One of the last iterations of this engine and classic model of BMW motorcycle.

    Back in 2014 I went on a ride with a group. We rode in Los Angeles from Pacific Coast Highway to Griffith Park Observatory in Hollywood. I think my bike was the oldest of the group. They stopped a few times on the way but I did not know why. I asked someone and they told me that many of the sport bikes were overheating and we had to stop a few times to let them cool down.

    My old R100R made it just fine.
    And riding two-up!
    Have a look if you are interested.
    ShadowBoxer video 0011 {PCH to Griffith Observatory}

    With proper maintenance these were built to last.
    And they do.

    Happy New Year and may it be a productive and happy one.

  5. I’ve owned a /5 since 1996. It’s a wonderful design and still a very useful bike. For most of my trips, it’s a better adventure bike than my R1150GS.
    And they are pretty indestructible. The author compares them to an anvil. But I think a hammer is more accurate. You’ll never wear out a hammer as long as you replace the head and the handle when it needs it.

  6. One of the few bikes out of many, many owned that I wish I’d kept was a 1970 R50/5 that I once owned. In hind sight I realize that It was the prefect bike. Miss it

  7. All of this talk of slash 2s and slash 5s is all well and good, but I’d like to comment on how dang cute the author’s wife one her first bike is. If there was a poster of that shot, I’d pin it up on my garage wall.

  8. My first BMW was a 79′ R65LS with duel plugs in the toasted orange color whose official color name I don’t know.

    To help understand where the BMW design teams’ heads’ were at at the time the /5 was developed I find it helpful to compare what was being produced and raced by the other brands at the time. I’d love to hear more about how and why BMW made it’s choices like including the seemingly out dated four speed. My next BMW would be a K75rt and even it seemed to be short changed by its designers with a five speed.

  9. Hi Guys

    It’s interesting to see all of your Airhead stories! We’ve had a few in our family besides the /5s. We started with a 1973 LWB R75/5 for me and my then girlfriend (now wife) pictured had the 1971 SWB R60/5. Then I got a 1974 R90/6, and then I replaced that with a beautiful 1977 R100S cafe! You can see these bikes here

    We eventually gravitated towards more modern BMWs when we started to ride longer distances together. I had RTs and Terri had R1150R and R850R set up to tour. Terri quit riding after we got married and she got pregnant. She hasn’t been on a motorcycle since! But I’ll pass your kind comments on to her. I’m sure she will appreciate it!

  10. Bought one in Perth, Western Australia, in 1972, and took it around the top following the coast, more or less, to Hobart and back to Sydney, where I had it shipped to Rotterdam for, I think, about 160 Ozzie dollars. The Metzeler tyres didn’t like the hot tarmac. It went fine on the dirt and gravel. The seat attachment was aluminium and rather crappy, I thought. I had one broken, which was replaced by BMW free of charge. In Holland I didn’t do a lot of miles. I sold it a year later when I moved to Canada (Richmond Hill, initially). The carbs, Bing: didn’t like them at all. Couldn’t get them to suck air with enough gas when opening up- Maybe my lack of nous?


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