Project BMW
Matt's BMW was meant to be tucked away. Awaiting its turn on the bench – but excuses keep being heard and BMW parts keep emerging…
This month the forks get checked, serviced and cleaned and the wheel gets pulled apart for some shiny new spokes – almost
Ishould be working on other things. The Norton, the Hondas, my other BMW; the house, for heaven’s sake. But the ‘new’ R100S fills my head with thoughts of long journeys, fulfilling its original brief; to take its pilot, passenger and luggage far and away, in style, speed and safety.
FAIL
As I said last month, the plan was always to hear it run first, to see if there was anything glaringly wrong. But the carbs were seized solid and the electrics, which largely live under the tunnel of the fuel tank, seem to have attracted moisture (the tank still had petrol in after 27 years standing) and are riddled with rust. Needless to say, regardless of fiddling and even with rebuilt carbs, nothing was alive. Disappointed in my failure, I decided to strip the bike without getting it started, as I need to paint the frame and I’ve always wanted to rebuild a boxer engine. Which may, indeed, be a decision I regret.
RESTORATION PROCEDURE
Many times before the idea of restoring a bike, or car, has been to strip it, taking notes and photos to help the rebuild, catalogue and store said parts, then to rebuild parts as you put it back together again. In reality, my restos usually win at the stripping stage, but then the pile of parts don’t get catalogued, but are distributed to various sheds, outhouses and parts of the house; for years. Then, surprise surprise, I attempt to rebuild the bike and can’t find anything. Maybe my true vocation should have been a scrapyard owner.
Due in part to space, time, money, impatience and the position of the moon I’m doing this bike differently. As I take parts off, I’m repairing/ renovating/ rebuilding them. The carbs are all ready to rock and now it is the time of the front end, starting with the forks and wheel.
TIGHTNESS – THE TELLER OF TRUTH
One thing that has struck me with this bike is despite the 65,000 miles it has covered, the majority of nuts and bolts are untouched and of the correct, factory torque. It’s a wonderful pointer to the fact that only those of competency have been here before. This bike has not been a ‘fiddler’s’ machine. I will try to break the habit of a lifetime and continue this trait, which is a lot easier than the Norton that sits next to the BMW, as I have spare stainless metric nuts and bolts and both a UK-published Haynes manual, an American Clymer manual and a BMW factory one, too – so no excuses Hull!
WAR ON THE FRONTLINE
The handlebars, which are unique and a rather unusual shape on the RS, are no longer available from BMW. And because of the acute angle, are hard to locate. Mine are original with a knurled-over end and good chrome, which should clean up. I would look at alloy ones to reduce weight, but I have yet to find any. The risers are alloy and one has badly corroded, trying to mimic the Norfolk coastal erosion – so I’ll look for one of those. The switchgear looks alright, the wording is coming off, but all switches seem to work and the wiring doesn’t feel too brittle.
The top yoke nut and fork top caps screw down to hold the top yoke; a most un-BMW piece of ugly steel plate (which is too thin to hold the forks rigid on a ‘sportsbike’ but you cannot see once the rubber pad is in place). The central nut and fork tops are 36mm, and held to a tight, 78lb ft. I had to buy a 36mm socket, which thanks to the 5mm thickness of the fork tops, had to have the flanged sides machined down to prevent it from slipping. Well, I say machined; it should have been, but it wouldn’t quite fit in my lathe chuck so I used an angle grinder! Then the top yoke nut needed heat to come undone. You know the feeling when a bike is fighting you?
But it did the trick. Loosened from the clutches of their top nuts, the forks refuse to come out of the bottom yoke. Oil? No. gentle persuasion with a screwdriver in the expanding gap? No. Bugger; just get the soft mallet. With top caps back in, this did the trick, but felt wrong. And I had been told the fork gaiters had been replaced – though I never asked when. But they felt nice, so I’m guessing just before it was laid up, so little chance for UV rays to stiffen them up. They have a hollow locating pin, which acts as a breather, so they don’t groan like an old smoker as the forks move.
FORK CANDLES
The chrome was in good nick apart from one rusty sport at the end of the travel on the left leg, just below the bottom yoke. I’ll clean it and try to Superglue it, as it should only get near the seal under very hard braking. Otherwise, all looked good.
Next the rubber bung at the bottom was prised off, revealing a 13mm nut that holds the damper rod to the fork bottom. With that undone, the 36mm socket came to play again to undo the bottom nut, so the damper and tube could be removed. A rubber donut pops out (the bump stop) so make sure that looks alright. The oil looked clean if dark, so another good sign. I thought of taking the damper apart, but it needs a special tool with two prongs to undo the damper from the stantion, and as the action felt fine, I cleaned up with some brake cleaner and gunk, then left it to soak.
The fork lower was fine, if horribly dirty. And I’ve been taken by the 1980 ‘Exclusiv Sport’ special edition, which limited to 80 bikes worldwide (50 to the USA apparently) was silver with blue stripes in the style of the yellow/orange red stripes on my bike. Though my bike’s stripes are painted, whereas this ‘special edition’ is just vinyl don’t you know… Oh yes…
Gloating aside, as mentioned before, they had polished fork lowers, final drive casing and the ribs on the rocker covers. But looking at books, internet and even an original feature sent in by R90s owner, Peter Simms (thank you, Peter, a very interesting and informative read), I cannot see if the casting texture on the parts were rubbed down to smooth and then polished, or just polished and left as is. Afterall, BMW kept their alloy as relatively grey in finish as standard, so polishing would have stood out. Only bikes that have been (overly) restored have a smoothed finish that I can see. The most attention to detail I usually show is petrol or diesel at the pumps; so this is all new to me. Thank heavens I’m not into concours…
Any how, I taped up the ends of the lowers and used glass bead to get the finish clean and uniform. 60,000 miles of brake dust and stone chips had left their marks, so it was nice to see them come out looking good, if matt in finish. Next I took them to a 6in brass wire wheel on a bench grinder, which brought the finish back to a lovely shine – where it could get to the alloy. A 6in wheel won’t get into the nooks and crannies, so a Dremmel tool with brass wire end finished the job nicely.
That looked good and hadn’t taken much time. But it wouldn’t last, so I got to the mops and soaps with a drill to clean up and polish the legs properly. I want
to expore polishing further as I know I’m not doing it correctly, but I followed the basic instructions and went from coarse mops and soap down to the softy softy mops and finally the old Autosol.
Initially, I couldn’t see the difference, even though I’d spent around 40 minutes on each fork lower. But when you compare, you realise it is smoother, more shiny and more protected. I may yet do them again, then I’m going to use 2k lacquer to give them some protection – then they really should shine. I’m not looking forward to the final drive though…
AND FINALLY
I am really pleased with the forks being straightforward and looking good. I think I need new polishing mops and be stricter with cleanliness to get a better result – I also could do with a more powerful grinder – but we all think we need better tools. There are new fork seals in and once in the bike, I’ve got some of Rock Oil’s best to pour in. Just keep an eye on fork oil levels, as there was a misprint in early manuals which was adjusted in later books. The springs look fine and equal in length, so I’ll use them and look into new or progressive ones if I need. I’m not into modifying things just because everyone else does.
“It’s a wonderful pointer to the fact that only those of competency have been here before. This bike has not been a ‘fiddler’s’ machine.”
FRONT WHEEL
This looked terrible, with rusty (chromed-plated originally I think – you can still see some flaking off) spokes and flaky hub. But the spoke nipples all look fine, so the alloy rim looks in great shape with no corrosion. In fact, with a little polishing, it came up beautifully – I may one day have a shiny bike! With a couple of straight edges I took some measurements to be able to strip and rebuild the wheel. I also took photos and notes of the spoke pattern, but the BMW wheel is really quite straight-forward compared to some, like Rudge!
I was already with the wire cutters and tyre levers – but I could not get that tyre off. At least 27 years on that rim has got it all comfortable and in no rush to be taken off. So I’ll have to wait until I can get it to a friend’s shop with a hydraulic machine – and a project bike’s wheel is not exactly essential travel… But I know that’s an evening’s job all waiting. Sometimes it’s the small things that hold you up.
NEXT MONTH
The calipers and master cylinder get a clean-up and service – and hopefully the wheel gets built.