Off The Road Blues
There are some bits of routine motorcycle maintenance which, at least theoretically, are associated with minimum mechanical risk and potential for drama.
These are the jobs you’ve done a hundred, or a thousand times – oil changes, tire changes – wrenching you could do in your sleep. In the dark. In the rain.
If, however, one is working on an original, unrestored 45 year old motorcycle, the No Drama Principle apparently expired about a decade and a half back.
My R90S is half tough on tires. This motorcycle simply vaporizes rear tires. The big bore 1000 cc motor delivers big, throbby power pulses to the rear contact patch, and, if one rides it like I tend to, with the right grip rotated most of the way around most of the time, that behavior tends to result in pretty diminished rear tire life.
On the flip side, the front tires last nearly forever because they spend so little time bearing any of the motorcycle’s weight.
Lose some, win some.
Losing this one, though, meant ordering up a new rear tire as my favorite Michelin Pilot Activ was doing a creditable impersonation of a racing slick.
My buds at Fredericktown Yamaha Triumph have helped me out with mounting motorcycle tires for years, which is pretty swell of them considering they don’t technically work on my brand of motorcycle. Since it seemed to me at the time we were all destined for some form of non-trivial commercial disruption – which, knowing what we know now, we were – I rang ‘em up and had them order me a tire, tube and while we were in there, a new rim strip. The day before my stuff was supposed to arrive, I went out into the garage to pull the rear wheel from the bike.
For folks that haven’t had the pleasure of changing a drive wheel tire on an old BMW, all I can say is that when things go smoothly, it makes pulling the wheel from a chain drive bike look like the messy, finicky, dirty nightmare that it really is.
On the Beemer, one loosens the axle pinch nut, removes the bolt from the end of the axle, pulls the axle out of the wheel, and then pulls the wheel off the drive spine and off the bike. It’s fast, it’s neat, and it’s relatively idiot resistant.
During the construction of Teardrop Camper V 2.0, the R90S had sat outside for about four months – four months during which it rained and rained and rained.
At the time, I had ventured the opinion that the R90S had survived that indignity with seemingly no impact.
That opinion was not correct.
When I went to pull the wheel, I removed the axle nut, loosened the pinch bolt, inserted the ‘tommy bar’ from the stock toolkit into the hole in the end of the axle, gave the customary twist, and the axle …. didn’t come out. I twisted a little harder, and it still didn’t come out. I applied some serious force, and the wheel walked off the drive splines…. but the axle still didn’t come out.
I know, sadly, from experience, when I am tiptoeing up to the threshold of doing something really boneheaded, so I elected to withdraw.
We are always stronger together, so I sought the advice of many wise and experienced people that I was pretty sure had been here before. With their information and less wisdom in my head, I at least had a good idea of how the whole bearing stack worked, and what I was likely going to have to replace to get it all back together.
I spent several days soaking things down in penetrating oils, heating things up with torches, whacking things with punches, including some things I actually wanted to be whacking… to absolutely no effect whatsoever.
On or about Wheel Gone Awry Hostage Crisis Day 10, I made exerted myself to remount the wheel on the drive splines and secured it in place with one of the carpenter’s clamps that is part of the Teardrop Construction Toolkit. A final circuit of penetrating oils, heat, and some whacking with a punch finally got the axle the remaining 30% or so out of the wheel, and revealed what had been driving me nuts.
One of the jauntily named Top Hat spacers – the one on the side opposite the final drive – had rusted, and in that rusting, had essentially welded to the wheel bearing’s inner race. It had also corroded internally so that the clearance between it and the axle had been so reduced that it wouldn’t let the axle slide through it – when the axle finally came free it brought the spacer and the attached bearing roller cage with it. One could also see where the spacer had been riding on the axle – which was visibly burned.
I used a propane torch to heat the wheel and then drove the rest of the bearing assembly out of the wheel hub.
Of the Beemer Yodas I had consulted, The One Tom Cutter’s advice had proved to be the most prescient – he’d told me to just take the reciprocating saw to the axle because “everything in the wheel was going to be trash anyway”.
Trash was clearly what we had. That saw would have saved about 10 days.
Pretty Sure That Didn’t Used to be Attached to That
Crap Bits. Like The Nice Burned Bit on the Axle?
The day before I started working on this bike, I’d briefly kissed one hundred miles an hour while out riding the S.
Clearly I ride with some form of celestial rider aide.
Before this bike would roll again, everything inside this wheel hub would need to be replaced.
I spent the normal hour or so looking for all the bits I would need, and whether I had any options as to where I could buy them. I needed a new axle, washer and nut, a bearing set, seals, gasket, inner and outer spacers, and both top hat outer spacers.
Ebay found me a vendor that majored in selling stock he’s purchased from dealers that were liquidated – he had a new axle, washer and nut for $79 – BMW NA price would be over $150. All Balls Racing has a kit with both bearings and all the seals for a fraction of dealer price. I’ve used their bearings before in the LT and was very happy with the product. The bearing sets BMW has in stock – clearly visible in their online catalog pictures — are offshored Asian-manufactured bearings, so are not worth the large cost differential they carry.
I did go to a trusted BMW dealer to get the spacers and gaskets that only they could provide.
Then, there was the small matter of the ‘wedding band’.
This older BMW wheel bearing stack design is about one thousand times stronger than is required for operation of a solo motorcycle. German engineering has a reputation for being extremely robust and somewhat ingenious – these roller bearing wheel assemblies are an easily analyzed object lesson in engineering overkill.
The older BMW wheel bearing assemblies were originally designed with the massive side loads required for sidecar use in mind – but when the sidecar lugs disappeared from the frames of the first /5 motorcycles – this wheel bearing design stayed behind. Two wheeled motorcycles have dramatically lower side loads on their wheel assemblies – cornering loads are converted largely to straight up and down, or ‘normal’ loads because of the lean of the motorcycle – the load always goes straight down through the center of the wheel and into the tire’s contact patch.
To manage the dramatically higher loads and side loads of the sidecar, though, BMW used precision tapered roller bearings in wheels where most other manufacturers use ball bearings. In order for these tapered roller bearings to provide durability in service, the spatial relationship between the moving components of the bearings need to be set to a defined preload, and BMW accomplishes this though an ingenious arrangement of an outer, fixed dimension spacer – that supports both bearings’ outer races – with an inner spacer whose dimension can be adjusted though the use of a circular insert that looks exactly like a wedding band, if our wedding bands were made of tool steel. The BMW parts catalog lists, I believe, thirteen different wedding bands all differing in thickness by .25 of a millimeter. For the home mechanic, this is a little inconvenient and ungainly, unless you think you are going to be doing a lot of these, and want to buy the entire set. Personally, this is the first one I’ve done in 35 years and over 200,000 Airhead BMW miles, so that seems like a stretch.
Fortunately, there is Cycle Works, a classic and antique BMW motorcycle tool supplier. I’ve had several of their well-built custom tools – an alternator rotor puller, and a clutch centering arbor – in my tool roll for years, and this job was an opportunity to add another, along with one of their ingenious solutions. In order to set the preload on the bearing stack, one needs a precisely made spacer to replace the final drive on the axle. Cycle Works had figured out that thirteen wedding band sizes was another kind of overkill – two strategically selected bands and many thin shims were sufficient to obtain the full needed range of adjustment. Another internet order was placed, and I and my cat set about waiting for the UPS man to come.
On the third day, the Cycle Works order showed up, and their spacer tool – used to set the preload on the bearing assembly – was the type of precise, robust and long lived toolmaking exhibited by the tools I had purchased from them 30+ years previously.
My BMW parts order – normally received in one or two days – was nowhere to be seen a week after the fact.
I made a call to my FNSLD*, and asked them what was up with my order. Under duress, they admitted that several of the parts I’d ordered were not stock items, and had needed to be ordered from Germany. It seems, rather reasonably in retrospect, that the internal wheel spacers I’d elected to shitcan in my wholesale replacement of everything that had been stressed by this failure, were so robustly built that no one had ever needed to replace one before, ever.
Best case was that they expected to receive my spacers from Germany in about 10 days, and then all would be right with the world.
Has anything you can think of been going best case, these days?
On the Twelfth Day, I phoned them again.
On this phone call, the dealer informed me that BMW’s North American parts warehouse had experienced an outbreak of The Disease, and had been closed for decontamination. The dealer anticipated that the warehouse would reopen the beginning of the following week, and that my backordered parts would arrive at their location a few days following.
Have you ever had a tire change drag on so long that you were starting to regret not having added fuel stabilizer to your gas tank before beginning?
I now apparently had.
On the Friday of the week following, my UPS man showed up with a small box. The box contained all of the spacers required to reassemble the bearing stack for my rear wheel. Courtesy of Illinois BMW Rider Trig Haroldson and his instructional video – https://www.youtube.com/watch?v=IXj01hUKJBg – I now had as thorough an understanding of the BMW tapered wheel bearing stack as it is possible to have for a man that has never worked on them before. It took all of about 20 minutes to set up the bearing preload, and another 10 minutes to grease the bearings and reassemble the stack. I then wrapped the entire assembly in a one gallon Ziploc bag, and put in in my freezer overnight.
The next day, I took my trusty propane torch in hand, and set about heating the hub back up to the required 250 degrees f. I use a glass of water in place of fancy measuring gear – when a drop of water dropped onto the casting boils off on contact, it’s hot enough. I pulled the axle and bearing stack assembly out of the freezer, sat it in the wheel hub’s opening, and gave a single tap on the end with a hammer. The bearing stack dropped smartly right into its proper position. Thirty minutes of cooling off and simultaneously warming up later, the races were held firmly in place.
One has to love thermal expansion and contraction. Physics is your friend.
A few more moments of wrenching reattached the bearing retainer, its gasket, and inserted the top hat spacers and the external seals. I marked the wheel’s direction of rotation on a bit of painters tape, and hopped into the wagon to run the rim up to Fredericktown Yamaha.
The next morning, I got my call that the new mounted tire was ready to be picked up. A few minutes’ drive, a few much needed minutes of moto-banter (at a socially acceptable distance, natch) with Ian Riley, Fredericktown’s GM, and a few more minutes’ drive and I was finally in position to put this motorcycle back on the road.
I spent a few minutes with the brake cleaning spray and some clean shoprags to make sure the brake drum surfaces and pads were free of any of the goo that might have resulted from my initial penetrating oil frenzy. Ian had related that the oddball setup of the airhead bearings and their captive asymmetrical spacers had confounded the shop’s spin balancer, which necessitated a few more minutes with my Harbor Freight static balancer, which is worth every one of the nineteen dollars that it cost.
Professional shops install BMW airhead tires with a motorcycle lift that has a removable rear platform section that allows the tire to be inserted from beneath and remounted on the bike’s final drive splines. Shamieh’s Shop uses a different method – thirty plus years ago Sweet Doris from Baltimore learned to hang wheels on the drive splines of a bike that I would lean over to the right and support while it rested on the main stand. My recently obtained wisdom to only use tires that are available in the stock 4.00 x 18 sizes have made that job so easy she looks like an endurance racing team pit pro – 4 seconds and she’s wrapped up and back over the wall.
My brand new lightly greased axle went back together more easily than any other tire change I can remember. Now armed with better knowledge of how these wheel and bearing assemblies work, I was careful not to overtorque the axle nut, and then cinched down the axle pinch bolt, and reinstalled the left side muffler that I’d dropped when things had started their decent towards the pearshaped. This was now, shockingly, a road worthy motorcycle.
I moved the Slash 5 out of the way, and then rolled the S out into the driveway. I swung a leg over and pushed the bike down the driveway’s gentle slope – with the clutch pulled in, it rolled smoothly and easily down the hill. At the bottom, I stopped and rolled the bike back and forth, forwards and back. Since everything seemed to be nominal in unpowered mode, I put the bike up on the main stand, and went back inside to get my helmet, gloves and jacket.
There had been times – given the emotional and mental health stressors of the previous 6 weeks spent under quarantine – when I genuinely wondered whether my R90S would ever see the road again. I’d questioned whether parts would ever be obtained, having to come through an international supply chain that had been closed at least once for decontamination. I questioned whether the dealership where my tire, tube and rim strip were waiting for me would remain operational. I even questioned whether my health would remain unaffected so that my heirs wouldn’t inherit a do it yourself classic motorcycle kit after my demise (some assembly required).
I’d managed to persevere though all of that, though, and now the small hurdle was the same as it always way – had my own skills as a mechanic been sufficient, and had the job been completed correctly? A few yards of road would, as always, hold the answer.
I opened the petcocks, set the choke lever, and turned the key. The S was a little down on battery – the last time I’d charged it to full had been a week or two back. The engine swung through five or six compression strokes before firing once and stalling. I waited another ten seconds or so, and then went for a second run at it, giving the engine the tiniest bit of throttle this time. On the third compression stroke – just before my doubts blossomed into full blown concern – the engine fired, then fired on the other cylinder, finally coming up to a lumpy idle. I gave the engine throttle a few times, backed off to half choke, then no choke, and then gently revved the engine until there was enough heat in the system to allow a smooth idle and to take throttle off the bottom. I toed the transmission down into first gear, gave it a little gas, and expressed tiny gratitude as the clutch bit and the bike moved smartly down my street.
I trolled around the streets of my neighborhood, short shifting between first and second gear a few times, gratified at what seemed to be a very smoothly rolling motorcycle. My neighborhood has a small park, and I stopped there briefly to visually inspect everything to make sure all the fasteners were still there and nothing was barfing any fluids – all was well.
It was the moment where knowledge would turn to understanding.
I gassed it, and turned right up the highway.
It didn’t take more than half a mile to know that this motorcycle and my work were good.
Tires that wear out affect handling far more than they affect traction. The new Pilot Ativ’s profile was absolutely round where the replaced one’s had been largely squared off. That square profile causes absolutely awful feeling stuff every time the tire drops to lean. And does it again when it comes back.
The new tire, though, with a perfect profile, was allowing me to lean and straighten up the motorcycle in a completely linear fashion. As I did the racer boy weave, gently working the tire back and forth to break it in, the handling ickies had been completely banished. The complete feeling of precision as the bike went onto the sides of the tire meant that the new bearings were set up at least well enough to fool me – there was no play in the rear suspension and nothing that felt like it wasn’t rotating freely. There is something about a BMW motorcycle that is has been set up properly that makes it feel like the entire bike has been made out of a single piece of metal, and that feeling was back.
Technically, my reason for being out of my house didn’t comply with the Governor’s quarantine order – I wasn’t out for work, food or medicine. I’m not sure that ‘being in pursuit of understanding’ would have cut it with the trooper.
Fortunately, I did not get the opportunity to try that one.
It did feel better than I can explain, though, to be in the saddle of this old motorcycle, with the thrust of this motor pushing me forward, and the wind washing over my body.
I kept speeds, lean angles and throttle openings easy as we broke the tire in and my confidence in the service rose. One never wants to fall off and go to the hospital, but in the time of The Disease, that preference goes at least double. I ran The Pike down into Knoxville, Mountain Road back up to MD 17, and then sat at the intersection, looking north and south and seeing absolutely no one else on the road. I was having a hard time adjusting to this present dystopia – the Disease had created a world where it was possible to imagine that there was only you – too many places I had been when on walkabout it had been only me.
I made the left to head up 17, back towards Burkittsville and back towards home. I got under the bubble and turned my left foot in towards the engine – a position that seems to increase the precision of my shifts – and took the bike up through the gears. About two thirds throttle and 6500 rpm seemed restrained enough to take the new rubber and new parts into account but enthusiastic enough to manage a few seconds of feeling free.
Banging through the 90-90s into Coatesville, and running the two decreasing radius right handers heading out were enough to convince me that all was right with the 58 inches of the world that lies between this bike’s two contact patches.
Now all we got to do is take tools in hand and fix what’s wrong with the rest of it.
* FNSLD — OK, If it is bugging you that much — Friendly Not So Local Dealer