This is a BMW R100S that’s been highly-modified from new, it now has twin-turbochargers (one for each cylinder), as well as electronic fuel injection, twin wastegates, an adjustable fuel-pressure regulator, and a Dyna electronic ignition system.
This bike was completed in 2016, it promptly won the Motorrad Award at The One Motorcycle Show and then placed second at The Quail in the Custom Motorcycle class. It’s now being offered for sale out of Miami, Florida.
Fast Facts: A Twin-Turbo BMW R100S
- BMW introduced the R100S model in 1976 as the successor to the R90S, alongside the fully faired R100RS. Powered by a 980cc air-cooled boxer twin producing 64 bhp initially and later 69 bhp, it had a 5-speed gearbox, shaft drive, upgraded suspension, and twin front disc brakes. Production ended in 1980 after 11,762 examples had left the factory.
- This heavily modified 1980 BMW R100 was built by Chris and Rebecca Canterbury of Boxer Metal in Chico, California, in just seven weeks for the 2016 One Motorcycle Show. Inspired by European vintage drag bikes, the project involved fitting individual turbochargers to each cylinder and radically modifying the motorcycle’s chassis.
- The engine keeps its original crankcase, cylinders, and heads but gains twin T3/T4 turbochargers, electronic fuel injection, twin wastegates, blow-off valves, Dyna ignition, and an oil cooler. The chassis was stretched six inches, lowered four inches, and converted to a hard tail, with an exposed driveshaft and rear drag slick.
- Finished in gold metal-flake with hand-painted pinstriping, it has a modified Dnepr fuel tank, custom seat, clip-on handlebars, and integrated boost gauges. It won the Motorrad Award at the 2016 One Motorcycle Show and placed second at The Quail.
History Speedrun: The BMW R100S
BMW gave the world its first glimpse of the new R100S model at the IFMA show in Cologne in 1976, it was the successor to the hugely popular R90S, and there’s no doubt the new model had some rather large shoes to fill. It was launched alongside the R100RS, that model was the new flagship of the range, it had a full fairing mounted to the frame, and was aimed squarely at more riders looking for a cross-continental sports tourer.
BMW gave the world its first glimpse of the new R100S model at the IFMA show in Cologne in 1976, it was the successor to the hugely popular R90S, and there’s no doubt the new model had some rather large shoes to fill. Image courtesy of BMW Motorrad. Image courtesy of BMW Motorrad.
BMW reached its 1.0 liter (actually 980cc) displacement by boring the air-cooled flat-twin out from 90 mm to 94 mm, and left the 70.6 mm stroke alone. Pushrods and rockers still worked the valves from a single central camshaft, and the compression ratio was 9.5:1. The R90S’s Dell’Orto carburetors, which had accelerator pumps, gave way to 40 mm Bing constant-velocity units, a move made chiefly to cut emissions.
At launch the engine made 64 bhp at 6,600 rpm, then from 1978 it was rated at 69 bhp at 7,250 rpm. Power went through a single dry-plate clutch and a 5-speed gearbox to an enclosed driveshaft, with a final drive ratio of 2.91:1 – slightly taller than the R90S’s 3.00:1.
The frame tubes kept their earlier Norton Featherbed-influenced design but gained thicker walls, and a new horizontal tube braced the downtubes just below the steering head. Together with an uprated swingarm, the R100S had a telescopic fork and twin Boge shocks carried over from the R90S, with stiffer, more sporting suspension at both ends than the touring models.
Up front you’d find twin drilled discs with ATE calipers, the 1977 bikes had wire wheels and a rear drum, but BMW introduced cast “snowflake” alloy wheels and a Brembo rear disc during the 1978 model year (which began in September 1977).
In the United States, the R100S cost $4,195 in 1977. It covered the standing quarter-mile in 12.97 seconds and crossed the line at over 103 mph. Not bad numbers for a machine of this type at the time. The R100S never matched the R90S’s sales, it sold 11,762, against 17,465 for its predecessor. Production ended in 1980 and for the 1981 model year, BMW replaced it with the R100CS – which had the 69 bhp twin and a sports cockpit fairing.
The R100S was launched alongside the R100RS, that model was the new flagship of the range, it had a full fairing mounted to the frame, and was aimed squarely at more riders looking for a cross-continental sports tourer. Image courtesy of BMW Motorrad.
The Twin-Turbo 1980 BMW R100S Shown Here
Chris and Rebecca Canterbury of Boxer Metal in Chico, California, built this twin-turbocharged 1980 BMW R100 for the 2016 One Motorcycle Show in Portland, Oregon. Remarkably, they had just seven weeks to complete it after the motorcycle they had planned to exhibit was shipped to a customer in Guatemala.
Inspired by Europe’s vintage drag-bike scene, Chris used the deadline to pursue an idea he’d been tossing around for years – a hard tail BMW boxer with an individual turbocharger feeding each cylinder.
The 980cc air-cooled opposed twin keeps its BMW crankcase, cylinders, and heads, but its original carburetors were replaced by electronic fuel injection controlled by a MegaSquirt MicroSquirt system. Two T3/T4-style turbochargers send charge into the engine, each with its own wastegate and blow-off valve.
The bike also has twin oxygen sensors, an adjustable fuel-pressure regulator, Dyna electronic ignition, an oil cooler, and separate boost gauges mounted in the fuel tank. The original 5-speed transmission and shaft drive were kept, although the driveshaft is now exposed and the final-drive housing has been modified.
To make room for the turbos and associated plumbing, Chris moved the engine rearward and upward within the frame. The chassis was stretched six inches, lowered four inches, reinforced, and converted to a rigid rear end. A 21 inch wire-spoke front wheel is paired with an 18 inch Lester alloy rear wheel on the back, shod with a drag slick.
The BMW front fork, now fitted with heavier springs, provides the only suspension, other than the tire sidewalls of course. Brembo disc brakes are linked through a Magura master cylinder, and it has a front line lock intended for burnouts. Because why not.
The fuel tank is a modified Dnepr unit, it’s finished in gold metal-flake paint and it has hand-painted black pinstriping by Dennis Price. Boxer Metal fabricated the rear fender and integrated solo seat, the bike also has clip-on handlebars, rear-set controls, an Acewell display, and a custom 3D-printed headlight assembly. The tank’s “Mom’s Rocket” lettering is a nod to Rebecca Canterbury.
This is a BMW R100S that’s been highly-modified from new, it now has twin-turbochargers (one for each cylinder), as well as electronic fuel injection, twin wastegates, an adjustable fuel-pressure regulator, and a Dyna electronic ignition system.
The bike won the Motorrad Award at The One Motorcycle Show and placed second in the Custom Motorcycle class at The Quail in 2016, one of the most prestigious shows in the world. The Boxer Metal team later confirmed that they had never finished getting the motorcycle running, so here’s hoping the new owner gets it working and makes use of that front line lock.
It’s now being offered for sale out of Miami, Florida with a bill of sale on Bring a Trailer. If you’d like to read more about it or register to bid you can visit the listing here.
Images courtesy of Bring a Trailer + BMW Motorrad
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
