100 Pounds Lighter: Backdated 1150GS from Blunk’s Garage…
Introduced in 1999, the BMW R1150GS quickly began to accumulate awards and recognition. Cycle World named it “Best Sport Touring Bike” of 2000, and Ewan McGregor and Charley Boorman made the model famous in their 19,000-mile Long Way Round from London to NYC.
Today, the big “Oilhead” is widely revered as the last of the old-school GS models — a simpler, more analog brute than the machines that followed.
“The BMW R1150GS is the best of the ‘old-school’ GS models. Reliable and solidly built… Simple to maintain yourself and easy to find parts for, it is a cheap bike that makes for a great commuter or daily hack that is also more than happy to tour or adventure ride.” –Bennetts
Our old buddy Judd Blunk of Marin County, California’s Blunk’s Garage has nothing short of a BMW GS obsession, born largely from epic journeys to the far northern coast of Alaska, Nevada desert, Colorado aspen forests, and more. After retiring from an “unnamed German car company” a few years ago, Judd has even more to time to dedicate to his two-wheeled projects, several of which have been featured here at BikeBound, as well as at prestigious events like Austin’s Handbuilt Show.
For this build, based on a 2003 R1150GS, Judd took inspiration from the car world — specifically, the Porsche 911 “backdate” trend, where newer models are modified to resemble the classic “long-hood” models of the late 60s and early 70s. The result is a machine with vintage style and modern performance.
Judd succeeded in trimming some 75 lbs from his first GS Backdate (pictured above), which was featured in the 2025 Handbuilt Show. The ’03 GS donor for this build — Backdate II — actually came from his son:
“My son had another 1150GS that was his daily ride, and he wanted a recently redone R100GS Bumble Bee I had, and we did a trade (I think he got the best of that deal).”
This time around, Judd focused on shedding even more weight from the machine, getting it closer to the weight and handling of the legendary HP2 Enduro:
“I have had an HP2e in my past and always wanted a toned down version of that light nimble enduro.”
Judd modified a R100GS tank, seat, and rear rack to fit the Oilhead, giving the bike a more classic silhouette. Meanwhile it’s lost the weight and complexity of ABS, fuel injection, and DME, and Judd upgraded the bike with WP USD front forks (goodbye Telelever), an Öhlins rear shock, 21-inch front wheel, custom ignition, Motogadget electronics, lighter exhaust and battery, and much more. The result is lighter weight and less complexity…just like the beloved GS models of old.
Judd gives us the full story and rundown of modifications below, but suffice to say Judd managed to shave nearly 100 lbs from the stocker, getting it down to 405 lbs — within 20 lbs of the HP2!
In the Builder’s Words…
This is the second 1150GS I have “back-dated.” Seeing the craze with Porsche 911s and some other cool cars, and being “given” (it had back fees and was pretty rough) a 2003 by a friend who was moving to Japan, I started the first one in 2024.
I showed the Back Date at the Handbuilt show in Austin in 2025 and was surprised at the good feedback and general reception of the build. With the goal of simplifying, lightening, and making the stock 1150GS look better, I stripped every non essential part off the bike: Exhaust (23lbs), ABS pump and lines (13lbs), wiring harness (3lbs), tank and fuel pump (not sure), fuel injection system, etc., etc.
The first one went from a porky 505 lbs to a semi lean 430lbs and it is fun to ride — I retained the Telelever front suspension on that one but it is quick in the turns, has big brakes, and all the power you could want (at least for an old man). My son had another 1150GS that was his daily ride, and he wanted a recently redone R100GS Bumble Bee I had, and we did a trade (I think he got the best of that deal).
In doing some research, I found BERRT frames in the Netherlands makes a front subframe that removes the heavy Telelever suspension so I sucked it up and bought one. I have had an HP2e in my past and always wanted a toned down version of that light nimble enduro. So some notable elements of this build (and for details, if you look back on my IG feed, you can see the process):
- ABS removed
- Fuel injection removed
- DME box removed
- Custom designed ignition system using a Blunks Garage designed hall sensor mount and a EME ignition module
- Stock Pipe removed and replaced with a UNIT Garage GP pipe
- 21” front tire and wheel
- 320mm single brake (front)
- 17” stock rear wheel and tire
- ProTaper High Adventure bars
- MotoGadget M unit electrics
- MotoGadget M button
- Modified stock control buttons
- Acewell digital dash
- Cyclops LED front light
- Lithium Ion aircraft battery
- Modified R100GS gas tank
- Modified R100GS one up seat
- Modified R100GS rear rack
- R100GS turn signals
- 48/60 WP USD front forks
- Ohlins rear shock
- SC3 Smart Carb carburetors
This bike weighs about 410 lbs or so dry — my first version had a Blunks Garage-made aluminum tank, but I didn’t like the overall look so I modified the R100GS tank and seat to bring it all together.
Follow the Builder
Instagram: @BlunksGarage
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