There’s a downside to the current popularity of BMW customs: a certain ‘sameness’ creeping in. After all, there are only so many ways you can tweak that familiar frame and boxer engine.
This new build from Austria’s Titan Motorcycles is very different, though—and unlike many builds that try to be different, it works beautifully. You’d never guess, but it’s based on an R90/6 from the 1970s, which means it has the 898 cc version of the venerable air-cooled motor.
Titan’s Michael Siebenhofer came across the R90/6 while browsing an Austrian online classifieds site. “It was was offered as ‘individual parts’,” he recalls. “The bike was not complete at all.”
Michael was primarily looking for an engine, because two-valve airhead motors are becoming rare in Europe. So he met up with the retired gentleman selling the BMW, in a carpentry workshop in the middle of nowhere.
Moments later Michael was the new owner of a very old engine, as well as a frame, a set of forks, and a few other ancillary parts.
Back in Graz, Austria’s second largest city after Vienna, Michael debated whether to resell some of the parts on eBay, to earn back a few Euros—or to invest many more hundreds to make the R90/6 a functioning motorcycle again.
He decided to rebuild. After tracking down as many missing parts as he could, he tore down the engine and the Bing carbs in the basement of his house. “Out of public view,” he explains. “If a man works hard during the week, he’s got the right to have a hobby in his leisure time, okay?”
An R75/5 gearbox was grafted onto the engine, and an R45 swingarm to accentuate the vintage vibe. Michael didn’t want to take any chances with the shaft drive though, so he’s installed a newer R80/7 kardan setup.
As the months passed by, the old BMW started to take shape. Michael pillaged the shelves at Titan for what he couldn’t find online, and also stocked up on maintenance and repair items from a local BMW dealer. “It’s a good thing that the German spare parts network is almost at 100%, even for 1970s machines.”
A concept started to form in Michael’s mind. “I had a 1920s tank concept, like a museum piece, or a racing bike from pre-war times,” he recalls. “But that style was not really feasible, due to the high frame beam of the BMW.”
Then Michael got his hands on an old tin tank from the 1930s, which he modified to fit—and then gave a subversive twist with BSA branding.
The seat support is welded directly onto the tank, with the original subframe brackets bearing the weight of the rider. It’s a neat arrangement, not least because Michael didn’t want to cut into the valuable R90/6 frame (which, incidentally, is homologated for sidecar use as well).
The Art Nouveau-style seat itself is a real highlight. It’s crafted in the style of the classic ‘Thonet’ Vienna coffee house chair, with contours cut out of a 50mm thick piece of oak plank.
Michael calls it ‘the real Austrian coffeehouse racer look,’ with milled grooves and an original Wiener Geflecht Viennese mesh insert. We’re told it’s very comfortable too.
The electrics, we’re glad to note, are straight out of the 21st century. A fresh loom is plugged into the latest version of the Motogadget m.unit control box, which feeds a Motoscope Mini speedo and m.switch pushbuttons. The turn signals are a mix of Motogadget and Kellermann, and the bars are LSL’s 22mm Drag Bars.
‘Stunning Sigrid’ was finished just in time for June’s famous Club of Newchurch Festival, which attracts 15,000 bikers every year to the beautiful Austrian Alps.
We’re not surprised to hear that the R90/6 won the Professional trophy in the festival’s Custom Bikes show.
And yes, it’s sacrilegious to sit a BSA tank on a BMW frame. But it’s also a much-needed touch of humor in the homogenous world of airhead customs.
Titan Motorcycle Company | Facebook | Instagram | Images by Clemens Humeniuk
