The BMW R100 was the last of the airheads, with nearly 1000cc of flat-twin punch on tap and all the history of the legendary boxer engine concentrated into a single machine. When Sebastien Ledis of France’s Seb’s Atelier first started customizing bikes, it was one of the models he had to have:
“It’s the myth of riding a flat twin BMW. It’s an icon…. Engine noise, vibrations, the smell of exhaust and petrol. And feeling the road at ground level. A real motorcycle. No need to have fifty assistances, fifteen thousand information points, as there is on new motorcycles today.”
Amen to that. Sebastien got this ’79 BMW R100RT dans son jus — in original condition, not restored or very well maintained. As this was a personal project, he was able to build the bike to his own tastes, free of any client design briefs or restrictions. A Ducati aficionado, Seb loves a sport-oriented riding position, and decided to transform the old airhead into a cafe racer, featuring a rebuilt engine, all new bearings and seals, Yamaha RD fuel tank, rebuilt brakes and upgraded suspension, a simplified wiring harness, and much more.
Below, we get the full story on this BMW “Blue Racer,” painted in Le Mans Blau.
BMW R100 Cafe Racer: Builder Interview
• What’s the make, model, and year of the bike?
BMW R100RT 1979.
• Why was this bike built?
It’s a personal project realized at the same time as my Honda CX500 Racer (The Low Rider), published on February 11, 2020. I bought the bike from one of my clients who would’ve normally had me make a preparation on it. The bike was still original, “in its own juice” (“dans son jus” in French).
• What was the design concept and what influenced the build?
I’ve had a lot of Ducati sport specials. So I prefer the cafe racer style for the driving position. I had already made three BMW R80 customs more recently for my personal projects. What I like to do is completely change the general appearance of the bike. And especially on a flat twin, replace its huge tank which looks a whale.
I had a double Yamaha RD50 tank in the garage following the transformation of my wife’s Suzuki GN, which I tried on the BMW. I found it pretty good! I had already seen a BMW with the same tank. A realization by a German at Wheels and Waves 2018.
• What custom work was done to the bike?
- The classics on the engine. A nice engine overhaul, gasket kit, pistons rings, adjust valves, carburetor repair kit, and synchronization.
- Brushed motor
- Battery box under gearbox and lithium battery
- Steering head bearings, swinging arm, ball bearing wheels
- Yamaha RD 50 gas tank
- Tommaselli handlebar
- BSA gas handle accelerator
- Fork lowering of 8cms
- YSS custom build shocks
- Custom saddlery
- Exhaust pipes and mufflers
- Rebuild calipers, aviation brake hoses kit, master cylinder
- New paint on wheels in silver and the rest in blue “Le Mans Blau”
- Aluminium rearset foot controls
- Mini switch controller
- Motogadget start switch
- Daytona Velona digital speedmeter
- LED lighting
- Simplified electrical harness
- Custom stop light with exhaust nut
• Does the bike have a nickname?
I don’t give my motorcycles a nickname. When I used it, I simply said, “La BM.”
• How would you classify this bike?
A classic cafe racer.
• Can you tell us what it’s like to ride?
It’s the myth of riding with a flat twin BMW. It’s an icon. When I started making preparations on motorcycles, it was one of the motorcycles that I had to have. Engine noise, vibrations, the smell of exhaust and petrol. And feeling the road at ground level. A real motorcycle. No need to have fifty assistances, fifteen thousand informations, as there is on new motorcycles today.
• Was there anything done during this build that you are particularly proud of?
I’m proud of the whole bike because I made it to my taste. It’s not like with customer motorcycles or there’s a specification to respect and that I cannot do what I want. (In French, “Le client est roi” — The customer is king.)
If I had to choose something that I’m most proud of , it’s the harness. I got it all out. On the old BMW R models, all the electrical harness is connected in the front light…real shit. I deleted everything: clock, voltmeter, cigarette lighter socket, alarm… I had to take out 30 meters of electrical wire. My biggest fear was that it wouldn’t start anymore!
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