Racebikes are just different.Everything they do is informed by leanness and purpose, and the best ones exude the thought, development, and preparation that went into them.Like this 1972 BMW R 75/5 built in the spirit of the early Butler Smith 750cc superbikes constructed at the dawn of the class. Everybody knows the R 90 S of Reg Pridmore, but there was a string of 750s that led to that spectacular 900cc AMA Superbike Championship winner in 1976.

The bike’s owner, Dan May, is the executive director of the American Historic Racing Motorcycle Association, so it makes sense his bike is finely finished.What makes less sense is why he’d agree to let me race it at Barber Vintage Festival October 11–13. Maybe the fact that he’s pretty busy that weekend running the whole AHRMA show and giving out awards, and also that BMW Motorrad Days Americas—the celebration of all things BMW—takes place at Barber during the same weekend, so perhaps there is some leveraging of media synergies going on.

For my part, I am beyond excited to try this bike in Formula 750 and BEARS classes, and get on the world-class Barber Motorsports track, plus finally get to visit the unparalleled Barber Museum.AHRMA makes it about as easy as possible to get on track, with classes to feature nearly stock bikes with basic preparation all the way to full-on historic racers like Norton Manxes and F-750 bikes. Have a 1980 Suzuki GS450 laying around or see one for sale for nothing? There’s a class for that. If you have even a whiff of inspiration to race, AHRMA’s roadracing, off-road, and dirt track programs make it exceptionally easy to get out there.

As a racer, May has an excellent record on track, and his bike is usually at the pointy end of the field. He’s done a huge amount of development work on making his 750cc flat-twin produce spectacular power with an exceptional torque curve. It rear-wheel dynos at 75 hp with the kind of linear output that wins on corner exits and puts a smile on your face.The engine modifications are under the strong influence of the Udo Gietl and Todd Schuster-built Butler Smith BMWs of the 1970s. Bores are nickel-silicon-carbide-plated by Millennium Technologies with custom 83.5mm Wiseco pistons with a healthy squish band and 11.5:1 compression. Stroke is stock at 70.6mm. Displacement is 773.21cc, the maximum allowed in F-750. Crank, rods, and cases are stock BMW (“All very robust,” says May) although he runs 1974 /6 components because they are stronger than the 1972 parts. May’s original 1972 /5 cases cracked, for example.The Rob Hall–ported cylinder heads run larger intake valves and smaller exhaust valves actuated by Smith Brothers chrome-moly pushrods. A “very radical” asymmetrically ground cam with relatively short overlap results in strong midrange torque and good top-end power. May has used beehive springs or nested dual coils, a necessity with the aggressive cam spec. A low-volume oil pump makes plenty of pressure at high rpm without eating too much horsepower—a trick from the Udo Geitl development days.

May spent lots of dyno time sorting out intake lengths and exhaust design, all the way down to and including filter length on the pair of Mikuni VM36 round-slide carbs (in place of stock Bing constant velocity carbs) allowed by the rules. The five-speed transmission features a low first gear for strong standing starts and close ratios for second through fifth (a very rare BMW gearset). It’s shaft drive (through a nicely braced swingarm) and May has a wide variety of ring-and-pinion sets to match gearing to the track.The bike was street-licensed when it began its transformation to racer, and the stock frame features side braces like those developed by Udo Gietl/Chris Hodgson (of San Jose BMW fame). The original 19-inch front wheel is replaced with an 18-inch 2.15-inch-wide rim (WM3) and the front drum brake replaced with a pair of Gremeca/AP dual piston race calipers.

A Continental CR 3 100/90 race tire is used at the front. The rear wheel is re-spoked to a 18-inch 3.0 (WM5) rim and offset to allow swingarm clearance (the shaft drive can’t be moved!) for the relatively wide Continental CR 3 130/90 rear tire. Cogent Dynamics “modernized” the suspension front and rear. A key difference is this bike retains dual shocks, whereas the Gietl/Schuster bike ran a custom monoshock setup.We were able to score a test day for me to get familiar with the bike in the weeks leading up to Barber Vintage Festival. Orange Cat Racing has a standing track day at Autobahn Country Club in Joliet, Illinois, and, as a BMW superbike/superstock team in MotoAmerica with at least one AHRMA-racing member, they shared that day with us.

Unfortunately it was exceptionally wet and miserable, although we got a couple hours at the end of the day to run on a drying, but never dry, track. I cautiously began to get familiar with the bike using low corner speeds, moderately aggressive braking, and dipping into that controllable power as much as I dared. The pace increased and I was delighted to find the bike easy to ride. Tragically, I tipped over looking to load the chassis more in the final session, and luckily did so in the slowest corner of the track so there was no damage to the bodywork and just a bent clip-on and a little scuffing on the right valve cover. May was incredibly gracious about my mistake. The bike is meticulously well prepared and sorted, right down to the new windscreen, and you can tell his attention to detail is fundamental to how this motorcycle runs and works. Maybe it was my factory-fresh Alpinestars suit that had never been on the ground? Here’s hoping we got all that out of the way.Fortunately May is about my size so the ergonomics and suspension setup are spot on. I also managed to get some heat in the tires even on a pretty wet track, and to ride with a couple of AHRMA regulars, albeit briefly thanks to the weather.

This 52-year-old BMW is a predictable, strong performing racebike that is a proven winner. Riding a safe, fast pace is up to me after the green flag drops. As a bonus, I’ll be testing a new BMW M 1000 RR at Barber the Monday after racing concludes, perfectly bookending the history of BMW superbikes from their birth in the 1970s to now, an increase of something on the order of 120 horsepower, 75 vs. 195 hp! Hope to see you at Barber. If you can’t make it, watch the website for a feature and check out the full-length video coming to the Cycle World YouTube channel.