BMW Slash 6
As time marched on and the market matured, BMW went big – introducing disc bakes, a 5-speed gear box, and bumping its three stock offerings up to 600, 750 and 900cc, respectively.
And with that great power, came the great responsibility to haul the bike back down from speed. Say hello to hydraulic disc brakes, standard issue (on the 75/6 and 90/6) for the first time in BMW’s history. With some exceptions, the tried-and-true rear drum brake would endure for the next 25 years of airhead development.
The /6 series also saw an upgrade to a 5-speed gearbox for greater range and higher-speed freeway cruising. Kick-start was no longer standard after the 1974 model year, but remained an accessory option. BMW’s whole line moved to the Bing CV carbs, which were smooth and dependable even if not exactly high performance. For that kind of hanky-panky, see BMW’s game-changing R90S, which also debuted in 1974 and came standard with Italian-made Dell’Orto pumper carbs—the only BMW model in this quarter century span to ever not come with Bings.
Other changes are less consequential: a redesigned dash assembly, ditching the single nacelle for a more contemporary plastic-clad twin gauge setup. It also got a real key, which worked on the ignition, the seat lock, and the steering lock.
First year /6 models came with holdover parts from the /5 era, with big knee-pad equipped touring tanks, and simple symmetrical Hella switches. By 1975 these had been replaced by more modern switchgear. The wheelbase was lengthened by about an inch over even the “LWB” /5’s to help stability at the higher speeds these bigger displacement bikes were now capable of.
Gone were the old stamped steel battery covers, traded for a new fiberglass side cover that would last as long as the twin-shock airheads continued to be produced through the 80’s. By 1976 a cottage industry of aftermarket fairing kits from Windjammer, Luftmeister and others had cropped up, and BMW’s ensuing family tree would split into a range of different models to suit the specific needs of the emerging touring and sport-touring markets.
In many ways the /6 is the apotheosis of the classic standard airhead. It had points ignition, crappy early disc brakes, and rounded styling and aesthetics which would soon look out of date as the 80’s approached. Bikes from the late 70’s onward would be burdened with a Pulse-air exhaust recirculation system, angular eighties-style valve covers, which would persevere into the mid 90’s, displacing rounded “peanut style” valve covers on previous few generations of airheads
Owners: Kat Connell, Blue 1974 R75/6; Dean Sharenow, Black 1976 R90/6