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‘Das Taco’ BMW R80 – Box-Werk Custombikes

Posted on May 23, 2016 by Andrew in Scrambler. 29 comments


Written by Martin Hodgson.

In the quiet German city of Oldenburg a highly skilled carpenter whittles away his days designing and crafting the finest furniture from timbers gathered from the local oak forests. But by night a darker side comes out to play, the chisel and mallet swapped for the tools of a blacksmith, here the carpenter turns motorcycle builder creating minimalist machines with the single purpose of carving up those same forests in a totally different way. Meet Marcel Papenberg who’s turned his passion and skill for motorcycle building into a second business, Box-Werk Custombikes, run in his spare time producing purposeful BMW’s from a collection of tired old machines just waiting to be restored.


In January this year Marcel picked up this 1983 BMW R80ST looking like an old “ugly duck” that in years gone by had served as a steed for the local law enforcement. Given that Marcel’s desire was to create a truly effective Scrambler the 80ST makes a whole lot more sense than many of its siblings from the all popular R series. It has all the torque you could want or need in such a machine with far less weight bringing it much closer to its British and Japanese rivals, “Kerbside, BMW’s ST would pass as a 500 in size, slim and neatly turned out” Motorcycle Sport observed at the release. But Marcel still had a lot more weight to save and it all started when he found the tank that now calls the backbone of the BMW home. Taken from a Bultaco Alpina 250 the legendary off-road marques tank surprisingly fits up well to the big German but it wasn’t ever going to be as simple as just the fit.


To start with the glass tank with its heavy “patina” was less than satisfactory inside and cleaning a fibreglass tank that has deteriorated that badly inside is less than fun with plenty of needle like pricks to the fingers removing gummy fuel. With a seal kit run through it the tank holds fuel like the day it was made, with a new petcock, filter and lines designed to work with the BMW arrangement. Marcel worked to get the small 250 tank to fit down nice and low and cover as much of the electricals as was humanely possible with such a tiny unit. But the outside of the tank is left completely as it was found, with all its motocross and trials battle scars, faded paint and vintage Bultaco graphics it’s not something you ever thought you’d see on a BMW. Knowing he had a tank that would work the standard item was put aside for another day and the bike stripped back for further fabrication. The long and weighty steel seat and subframe have been removed and in their place a new simplified subframe with a bubble back welded in place.


It’s not a feature you immediately notice but one Marcel spent considerable timing crafting as he wanted the subframe rails to match the seat he had in mind. “I made stencils for the rear frame, up, down, up, down, other, welding, adjust turn, is important to me to continue the lines of the tank and let be harmonious, it should look as if it belonged always so. The process of the rear frame was most intense of all components.” Over the top of the metal work a piece of flexible plywood was laid down to form the base of the seat and then cut to perfectly mirror the new steel. The base was built up with foam to form the shape, slim waist/big butt, before being covered in dark brown vintage Nappa leather by fellow craftsman and friend Albert. With the tank and seat combo now giving a true Scrambler feel with some vintage comfort the frame could be torn down for the final time. Sandblasted to remove all the crap it had collected over the years it was then sanded back before being given a coat of black powder coat along with the swingarm, upper tree and rear shock.

That rear shock is the 80ST specific unit that acts directly on the frame for greater feel, is shorter than the all-purpose GS design and provides the perfect level of absorption and rebound for a machine equipped with aggressive rubber designed not to bottom out on even the roughest of trails. But up front is where Marcel has made the big suspension changes with the conventional telescopic forks completely overhauled to give a ride capable of tackling just about any terrain. To accommodate the springs and raise the front end the stanchions have been extended by 60mm with the beefy ST lower tree doing the bulk of the clamping. Keeping unsprung weight down on lengthy shocks becomes even more important and the single 285mm drilled disc with single piston caliper has just enough bite without the brawn. Powdercoated hubs have been re-laced with lightweight spokes to new rims that have been wrapped in some serious mudslinging rubber.


Pretty sure it’d be resting on the cylinders without that chock…

Firing those rooster tails into the air is the classic BMW boxer twin with a deliberately low geared 5 speed designed to provide tractability on loose surfaces and the light ST flywheel providing snappy throttle response. The 797cc lump was pulled from the bike and given a full overhaul and a much-needed clean, with all exposed surfaces left in their standard metal finish. The metal airbox has been ditched for more weight saving and the twin Bing carbs now breathe through exposed individual pod filters. The simplified exhaust has been heat wrapped from the headers to under the engine where the two sides merge and exit on the open wheel side in a single blacked out muffler. The tiny Bultaco tank, reduced body work and tall front end means the airheads are not obscured from any direction that provides for a dramatic mechanical look, especially when taken front on.


To steer the R80 wide motocross bars make for drastically improved manoeuvrability and dressed up with small switch blocks and Ducati Monster master cylinder and levers Marcel’s machine looks ready for battle. But he couldn’t build this forest frolicker without attaching some of its raw materials and he put his wood work skills to use turning up a set of Oak grips. Then he ripped off the unsightly front shock mounted orange reflectors and replaced these with a set of his own hand crafted Oak inserts that like the grips are finished to match the colour of the seat. The bulky BMW dash has been tidied up with a side mounted speedo with inbuilt idiot lights and much of the wiring that was remaining routed through the handlebars. To finish the front end off a bracket was made to mount a small Bates-style headlight and even smaller Motogadget mini blinkers.


The finished product is what the BMW engineers would have built had they been allowed to sneak away to sleepy Oldenburg in the first place. Rather than the compromises made to meet the expectations of middle management they only got halfway there, but Marcel has completed the ST story of the early 1980’s which was never about creating a true Sports Tourer, BMW had plenty of those, it was about having fun when the bitumen ran out. With an array of motocross equipment, a legendary trials era tank and just the bare essentials fitted it’s a Scrambler not only in name but in action. But just as much as he loves riding Marcel is keen to get the next Box-Werks BMW underway, “This passion and obsession to build motorcycles is my blood… I cannot wait for the next project to start. In fact, it’s already in my basement!”

[Photos by Matthias Knust]

  • I will fab up a proper length side stand for you Marcel 😀

  • Hardley T Whipsnade III

    Yet another perfectly good Beemer ruined in the name to of pretense and the trend , not to mention the craftsmanship from top to bottom is highly questionable at best . Once again proving passion alone is not nearly enough .

  • The Ogre

    What an ugly mess.

    • the watcher

      Reads so perfectly as a comment with which to follow that piccy.

  • John Wanninger


    Bring on the ass patters- Call us all haters. In the name of art, beards and skinny jeans.

    Come on now- Tell us what’s great about this piece. Is it the wiring? Is it the way the spindly front end looks like it will snap? Oh I know, It’s the artfully short kickstand. So rebel.

    I knew it. You meant to do that. Nice job on the pipewrap. Looks good.

    • Honkylips

      Are you OK?

      • blackbird

        I think he spazzed out, I can feel the heat readiating off of him from here. So one time grounded out the diode board on my bike and when it went thermonuclear, it actually shot flames out of the front vent on the engine cover. Kinda like that you mean?

        • Honkylips

          lol, yes. Think he will recover? This might be the bike that kills him.

  • Alasdair Sykes

    I love aspects of this. The stance is gangly but kind of cool, it looks like it really would be at home on the rough stuff. The Bultaco tank is cool too, and I like the negative space it creates above the engine. But… it seems a little unfinished if truth be told. Standard length side stand, and pretty sure the centre stand is useless too unless that’s been modified, which seems unlikely. That sub-tank wiring loom…. ooft. And fenders anywhere? This bike has great bones but it seems like the builder got bored before the job was done.

  • Jim Roberts

    i’m trying to find the written equivalent for toilet paper so as too expunge this shitty mess. i’d be interested in a time lapse photograph of this bike sitting in the sun on a summers day……and then count the number of flies that landed on it, and then flew away discussted. to.

  • Jim Stuart

    If you locked a thousand Monkeys in room filled with the machines necessary to create a motorcycle maybe they would create something this bad. My bet is that they would rebel and turn to writing, then send out a draft of War and Peace as a manifesto to voice their displeasure.

    “The finished product is what the BMW engineers would have built had they been allowed to sneak away to sleepy Oldenburg in the first place.”

  • I thought that nobody could set the bar lower than Blitz, but I see now that I was completely wrong…

    • You, sir, win this comment thread. Couldn’t have said it better myself… This makes Blitz bikes look good!

  • weak stream

    Das Ca-Ca.

  • Dave Coetzee

    I just checked out some photos of the original R80ST and R80GS models and love what he’s transformed this bike into.
    With a couple of personalised changes, including an IT/YZ (early ’80s) front mudguard, I think it’ll be a hoot to ride.

  • Andy Rappold

    Fugly beyond words !!

  • Don Arnold

    Everyone else slams these bikes 30-40mm, so raising by 60mm gives a unique take on the airhead thing. But if you leave the rear down that’s a chopper, not a scrambler. Steering too slow. Think I’d like the oak grips.

  • Manx Ryan

    Wow, tough crowd. I like that the builder has actually put some thought into the suspension. I also like the tank and screw all the haters about the wiring, guess what everyone, that’s what they all look like under the tank, mine looks far worse even.

    • Tough crowd? Did you look at the photos? YEESH! Swapping out fork tubes is hardly putting thought into the suspension. A lot of factory wiring does look like that but it doesn’t have to and shouldn’t on a custom bike; especially if you’re going to make the decision to leave it fairly exposed like that. Never make excuses for poor craftsmanship.

      • Manx Ryan

        As spectators I think everyone is assuming an unlimited budget, rewiring the bike may not have been in the budget or part of the brief if it was a customer build, especially with the tricky charging circuit that BMW’s are lumped with. Anyway, too many armchair experts, I’m amazed builders even bother sharing their work on these sites any more to be honest.. and I certainly won’t be sharing my own when it’s done, I’ll be out riding.

  • jlgace

    I thought the comments were a bit negative, but also constructive. Having the bike you built posted on a blog is a lot better than most of us and I say congrats for that. Don’t be discouraged and keep it up. A custom bike only has to be perfect for one person, the owner. For the owner, I’ll add this to appreciate or discard – whichever they choose. I realize there’s a limit to how much travel you can get out of the rear suspension and maximize ride height without creating problems for a shaft drive. Like it or not, I think that simultaneously restricts your options for the front end in order to maintain decent geometry if you’re going to ride the bike. Extending the fork tubes is only increasing your ride height without effecting travel, yet messing up the stance and the geometry. Replacing or dropping the tubes in the trees will likely result in a surprisingly better ride. For the sidestand, throw it away and lean your bike against whatever is handy like every other dirt biker and as for the wiring, is it to show or ride? I appreciate that the builder did not reduce fuel capacity or chop up an original ‘glass tank to try and hide it though.

    • Don Arnold

      You could put a gs shock on and get the rear up. Don’t complain about u-joint life, as if this thing will ever make it out of downtown.

    • the watcher

      Negative comments are constructive, eh? So next time he’ll build something that meets the exacting standards of people who, for the most part, have never had so much as a picture of their own teensy winkies put up for public dismemberment (ho ho). And yes, I know that wasn’t your message, I just used that little bit as a springboard for my rant.

  • asdfasdfadcadcasdc

    An Artist’s rendition of what this bike might look like without the block.

    • asdfasdfadcadcasdc

      FYI, I don’t hate the bike at all, but I also don’t like it enough to stand next to it all day to keep it from falling over.

  • Tyler R. Gregorka

    oh mannn lol these comments are great lol

  • Looks useful…..

  • the watcher

    I like it, but I like Blitz stuff too (and Auto Fabrica, Kiddo, Church of Choppers, Full of Hate, and, well, you get the idea). I really just love motorcycles and you really have to be trying in order to fuck up something so brilliant. Think about it……

    • the watcher

      In fact, I’ve just skimmed down this page of PB alone and though I would have done some things different (or not at all) I’d still love actually riding every last one of them. Probably makes disqus pretty pointless though, eh?