Perilous Endeavor: A BMW R69 with half a car engine

Custom BMW R69 with BMW 700 engine
Old BMW airheads have always been easy targets for customization. The motors are simple and easy to work on, the bodywork is modular, and there’s a solid two-decade production run of interchangeable parts to pull from. One might even say they’re the easiest bikes to build—though we’d dare anyone to call this custom BMW R69 from Möbius Garage easy.

According to builder Sébastien Beaupère, this project has been in the works for over a decade. Design started back in 2012, and the bike has slowly been taking shape ever since, in his garage in the south of France. Ten years may sound like a long time for a single project, but once you get into the details, there’s no question about where the time went.

Custom BMW R69 with BMW 700 engine
Dubbed ‘Izarra 700,’ this BMW is a testament to what’s on offer along the road less traveled. Its recent first place win at this year’s Wheels and Waves festival in Biarritz was just as hard-earned as it was well-deserved, and the work that went into each exacting detail begs for a closer look.

Take Izarra’s engine, for example. You’d be forgiven for thinking this was just another early-model boxer motor that’s been polished up for display—but what you’re actually seeing here is a bonafide singularity.

Custom BMW R69 with BMW 700 engine
The block should be familiar to BMW connoisseurs of a certain distinction, as Sébastien sourced it from a 1955 R69. The rest of the motor, however, isn’t from a motorcycle at all—it’s from a 1964 BMW 700 automobile, which Sébastien painstakingly grafted into place against all odds.

“I realized that the stroke of the connecting rods of the car engine and the motorcycle were identical,” explains Sébastien. “Only the bore is bigger on the car, which makes for a hyper square engine. On paper everything looked simple…”

Custom BMW R69 with BMW 700 engine
In practice, however, Sébastien quickly found that there was nothing simple about the undertaking. The first hurdle was that the car cylinders didn’t quite match up with the R69 crankcase. He could have stopped there, but instead chose to refill the case openings with aluminum, and then re-machine them to accommodate the 700’s cylinders.

After that, things only got harder.

Custom BMW R69 with BMW 700 engine
Tubes and rocker arms had to be fabricated to the appropriate length. The car’s central intake layout was completely reworked to accommodate dual horizontal Dell’Orto carburetors. And custom exhaust outlets were machined from stainless steel.

Sébastien even chose to keep the car’s original four-speed gearbox, which meant that engine mounts had to be modified to keep the drivetrain properly aligned.

Custom BMW R69 with BMW 700 engine
Once the powertrain was finally finished, Sébastien applied the same uncompromising ethos to the chassis. He wanted to maintain something of a vintage BMW Rennsport aesthetic, so an Earles fork was the only serious choice for a front end.

A vintage unit was sourced, then modified to be shorter and wider in the name of performance. The front shock absorbers were upgraded to dual Öhlins units for increased compliance and adjustability, and an 18” spoked wheel was fitted to the front, wrapped in 140-wide Michelin flat track rubber.

Custom BMW R69 with BMW 700 engine
Izarra got the same performance treatment at the rear. By modifying a BMW /6 swingarm, Sébastien was able to stuff a 160-wide tire in there. It’s suspended from a custom-fabricated subframe with a second pair of Öhlins shocks.

The result is a stout performer with handling to match. Between the engine’s high-compression pistons, enlarged valves, tuned intake and exhaust ports and upgraded carbs, it now makes a healthy 65 horses at 7,500 rpm. But as sweet as this motor is, performance is only half the story; this bike is pure visual pornography too.

Custom BMW R69 with BMW 700 engine
Sébastien took his time with every single detail—like the fuel tank. He could have gone the easy route and maintained the classic BMW dark paint and ivory pin-striping that adorns the front and rear fairings. But instead, he covered the bulky Rennsport-style aluminum fuel cell with a radiant brass coating.

This theme continues through the rest of the R69’s details, from the engine’s brass rocker arms and freeze plugs, to the spacers at the shocks, and all the way up to the striking mesh windshield that sits atop the custom-made front fairing.

Custom BMW R69 with BMW 700 engine
Izarra’s tail cowl borrows its shape from the Ducati racers of the late 70s—like Mike Hailwood’s infamous TT-winning 900NCR. The split upholstery that sits on top was taken from an old Cessna airplane interior, making for yet another truly unique detail.

Everywhere else you’ll find clean lines and pure minimalism at its finest. Sébastien wanted to keep exposed cables and wiring to a bare minimum, which led him to ditch the battery entirely and rely instead on either a kick starter or a paddock starter—like a proper race bike. He even went so far as to route the hydraulic brake lines through the fork itself.

Custom BMW R69 with BMW 700 engine
Clearly, Izarra was no easy build. Ten years is a long time, but for Sébastien, it was time well spent.

Sure, you could argue that da Vinci only took three years on the Mona Lisa, or point out that the Statue of Liberty was completed in less than a decade. But neither of those can get your blood pumping like this two-wheeled fire factory—and for that, we say chapeau!

Möbius Garage Instagram | Images by Damien Lorrai

Custom BMW R69 with BMW 700 engine

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