BMW R80 Scrambler Project

Well here it is, I’ve finally managed to finish it after nearly two years of intermittent building, you know how it is, full on for a few days and then work interrupts and your project disappears under a blanket for another few months.

I chose the R80 over any of the other BMW boxer options as in my opinion its by far the best engine size for the boxer engine configuration, for me the 1000’s are just a little to vibey, just my opinion of course.

So I needed a R80 donor it had to be a 1982 onward with the lighter flywheel and modified clutch, I already have a very standard 1980 R80 but its far too nice to cut up. I find a 1986 RT advertised on eBay near Milton Keynes I phone the owner and a few moments later I’m in the car trailer hooked up and heading north. My first mistake was viewing the bike on a dark wet night and the second was believing a single word the seller said, he claimed he had just completed a 2000 mile tour of Europe, it was painfully obvious this thing wouldn’t make it to the end of the drive under its own steam…bless him, the third mistake was buying it.

So here we have it, trust me the photos flatter, I mean they really flatter, the following day was a day of reflection, mostly on how stupid I’d been in buying it in the first place, not for the first time and probably not the last either. But it is what it is, and for better or worse it’s all mine now, so a little less self pity lets get on with the job in hand.

The bike was stripped to all but the bare essentials as I needed to design a lot and visually see if it was going to work or not before fabricating a bespoke solution.

I wanted a single seat, so I took the original BM offering and literally cut it in half being careful to retain the original hinge and lock, all that remained was to fabricate the rear section this was fashioned from a piece of 2mm mild steel sheet and welded to the seat base to give the upholsterer a nice profiled edge to finish on,    

I did not want the battery on view, neither did I want it under the gearbox as I wanted to retain the centre stand, after a little research I was told the Motobatt MBTX4U was powerful enough to start the boxer twin, so I bought one and tested it on my 1980 R80 and sure enough she burst into life. Now where to hide it, I decided the best place for it was under the seat but even with battery on its side it was still visible, so I created a recess on the under side of the seat to accommodate half the battery, the remaining half sat on a plate that was mounted into the open end of the frame tube, this plate was adjustable to accommodate a larger battery should it be required at a later date.

The rear frame loop was cut off and I made a hoop to mount the mudguard on, both front and rear mudgaurds were supplied by Armours of Bournemouth just reproduction guards for a classic Triumph I believe, they both required a little tweaking, cutting to length etc and both were 20″ so had to be mounted away from the 18″ wheels to defuse the discrepancy. The brake calipers were completely shot along with the discs, I rebuilt the calipers with service kits and replaced the discs with good second hand examples, the fork stantions were bent beyond repair so they were also replaced with new.

With the battery now in its new home the rear mudguard exhaust and light mounted, frame stripped of all unwanted brackets, it was time for a quick mock up of the finished article before shipping the wheels and frame off for powder coating.

So with the engine on the bench it was time to strip it for inspection and prepare it for painting, the bottom end was sound so no need to remove the crank just some careful masking required prior to preparing for paint.

I had already decided to finish the engine in a specialist coating called Kal-Gard, this is a product originally designed to disperse heat from machine gun barrels, it’s a high particular paint that has an unusual texture/colour combination, it also has the added advantage of being extremely durable, it’s a real pig to apply but worth the agro, you can see more about this coating on my paintwork page. I chose to paint the Crankcases and barrels in a wrinkle finish Matt black paint and the engine extremities in Kal-Gard/Gun Kote.

So after replacing the starter motor, gearbox, barrels, pistons, heads, valves and guides, drive shaft, rear shock, brake discs, fork stantions all bearings  (remember what I said about buying a wreck of a donor bike) the engine was back in its satin black powder coated frame, along with a freshly upholstered leather seat.

The rear rack and tank knee pads were fashioned from a piece of 3mm checka plate I had lying around, once again these were finished in Kal-Gard, the strap hooks on the rack I machined from aluminum along with the retaining screws and washers on the knee pads.

Fork tops machined from titanium, and a nice pair of Motogadget bar end indicators to finish off, pricey but nice.

The headlight was replaced with a nice little 41/2″ number I bought from Germany, and the original speedo replaced with a digital Trail Tech.

So there we have it would I do it all again? You bet, would I do anything differently? you bet, I’d buy the very best donor bike I could lay my hands on and in doing so would half the build costs.