The BMW R80ST is one of the few classic BMW boxers that can legitimately be called lithe (relatively speaking, at least). Derived from the famous BMW R80G/S, the R80ST borrowed its sibling’s banana tank, scrambler-like seat, offset mono-shock, and tightly-tucked banana exhaust. Compared to its 1,000 cc stablemates, it’s downright skinny—but not skinny enough for STG Tracker.
Run by Marcelo Obarrio and Germán Karp, and based in Buenos Aires, Argentina, STG Tracker has a penchant for building aggressive street bikes. So machines like this svelte BMW R80ST street tracker fall squarely within their wheelhouse. The brief called for an agile boxer with sharp lines—and STG Tracker delivered in spades.
Marcelo and Germán started with a bone stock 1983-model BMW R80ST, but most of it ended up in boxes. The main frame and drivetrain are original, but everything else is either custom, aftermarket, or scalped from another motorcycle.
That said, the engine hasn’t exactly gone untouched. STG rebuilt it, gave it a fresh coat of paint, and polished the edges of its fins to add contrast. They also installed a set of classic BMW ‘peanut’ valve covers, and then trimmed the cooling fins on the cylinder heads to better complement the curves of the new covers.
The airbox has been ditched for a pair of K&N filters, with a new cover filling the space where it used to sit. STG rebuilt the carbs too, and fitted a pair of carb-mounted choke pulls, eliminating the need for a handlebar-mounted choke lever. The bike breathes out through new stainless steel headers, exiting via a single Spark muffler.
With no crazy engine or carb mods, STG’s goal was to improve handling and add lightness. And that called for a significant upgrade to the BMW’s running gear.
Up front, Marcelo and Germán installed the beefy upside-down forks from an MV Agusta F3, along with its twin Brembo brake calipers and discs. They then machined a new front wheel hub to match, lacing it to an 18” aluminum Akront rim. A carbon fiber fender hovers above the wheel, mounted on handmade fender stays.
A little further up, STG’s prowess with a CNC machine is on full display. When the shop isn’t hard at work building custom motorcycles, they’re designing and machining bolt-on parts for myriad applications. That’s why this BMW sports a smorgasbord of beautifully made parts—starting with an impressive set of fork yokes, with cut-outs that set the tone for the rest of the build’s bespoke bits.
The top yoke wears CNC-machined handlebar clamps, plus a custom housing for a digital Motogadget dash. It’s tucked tightly behind a handmade carbon fiber headlight shroud, with a Koso LED unit beaming out the front. Other accouterments include a set of tapered bars, new grips, a new throttle, Brembo controls, and switches, turn signals, and mirrors from Motogadget.
Out back, STG matched the front wheel with another 18” Akront hoop, this time laced to the OEM drum brake hub. The wheels are shod with Pirelli Phantom Sportscomp tires, while a YSS shock props up the rear.
A custom fuel tank and tail section sit up top. The two parts work in perfect harmony, cutting a straight line along the bottom and a flowing curve over the top. Sculpted knee indents help keep the BMW narrow between the rider’s legs.
STG fabricated a new subframe, and then closed it in with a handmade cover that sits below the seat. The fuel tank wears a pop-up gas cap and one-off BMW roundels, and the seat is covered in a combination of leather and Alcantara, with a pair of LEDs mounted below to act as taillights and turn signals.
Marcelo and Germán went back to the CNC machine to add a few extra details to the R80ST. The foot pegs and levers are new, and feature the same cutout vibe as the fork yokes. Then there’s the exhaust bracket; a wonderfully crafted piece that subtly mimics the shape of the subframe.
Well-judged finishes push the build into overdrive. STG chose a deep glossy blue for the bodywork, augmented by black pinstripes in a traditional BMW style. Most of the hard parts are black, except for the standout CNC pieces, which are simply clear-coated.
Visually and physically lighter than before, STG’s BMW R80ST street tracker firmly hits the mark. And if you need any more proof that Marcelo and Germán are at the top of their game, check back in a couple of weeks; we’ve already glimpsed their next build, and it’s a doozy.
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