People sometimes ask me, “Where did you learn how to fix your bike?” I answer, “I didn’t. I’m still learning.” Being a DIY guy is a never-ending process. But the start is usually the same: an oil change. The first thing I did with my 650GS is change the oil and coolant, and because we live in the YouTube era, I lucked out and found a great how-to video by Kirk of the BMW Motorrad Club of Northern Illinois doing this very service on my exact bike! I love Haynes Manuals, but there’s nothing like seeing someone do it “in person.”
From there, I changed my brake pads. Brakes! you say. Don’t you want to get those done by a professional? I know, there’s an emotional component to brakes, but the fact is, they’re really not that complicated—a disc squeezed between two asbestos-lined pads. When time came (40K) for valve adjustment, I did a bunch of research and plunged in. Each time I start a job I don’t know where I’m going but I figure it out along the way. As the American poet Theodore Roethke says, “I learn by going where I have to go.” And each time I go, I learn more about my bike.
Sometimes the journey is made longer because you don’t know what the cause of your troubles is. All you’ve got are the symptoms. In those cases, your diagnosis is easily half the work. Now if you are an experienced mechanic, you’ve seen it all and you can make an educated guess and save yourself a lot of time. Or you have a machine that costs the equivalent of my monthly wage and does the diagnosis for you. But if you’re a DIY guy on a budget, and this is the first time you’ve experienced these symptoms, you’ve only got the Fault Finding section of your service manual, the brain hive of a good user forum, and your intuition. Using these three tools in the right combination is the most useful wrench in your toolkit.
So when my bike overheated last fall after a little tip-over in sand, spewing boiling coolant out the overflow reservoir, I packed my bags and stepped out for a new journey, one that would prove to be especially long.
I don’t know how the editors of service manuals order the list of probable causes to certain problems. Do they list them in order of most probable to least, cheapest and simplest to expensive and complicated, or some combination of both? Since I’m on a tight budget, I tipped the scales toward cheapest fix first. Top of my list, then, were things like coolant level low, radiator pressure cap defective, thermostat stuck open or closed. So I started there, specifically with the thermostat. I took it out and tested it, sticking it in a pot of water on the stove with a thermometer. It opened just fine at the temp it was supposed to but didn’t close once the water cooled. Hmm . . . Could this be the problem? So off I went to BMW for a new thermostat. At $65, it’s got to be one of the cheapest parts on this bike, so I was hopeful I’d found the problem.
I put the new thermostat in and rode one block and the temp light came on. Damn!
Next I focused on the fan. Was it running when the bike overheated? I couldn’t remember so I texted my riding buddy. He couldn’t remember hearing it running either. Maybe there’s a problem with my fan, then? I connected it directly to the battery. It worked. Good, I guess. Maybe the sensor that turns on the fan is defective? My neighbours must have been wondering what I was doing with my camping stove out on the driveway beside the bike, but I had taken the sensor out of the engine block and was heating it in a pot of water, as I did with the thermostat on the stove. The fan did not turn on. So off I went to BMW for a new sensor. I was confident I’d found the problem.
I put the new sensor in, started the bike and ran it up to temp. The fan turned on. Great! Then I rode one block and the temp light came on. Damn!
Turns out the sensor works by pressure as well as temperature, so heating it alone would not trip it. On the plus side, the fan was turning on, so I knew that system at least was working properly.
The most recent time the temp light came on I noticed some coolant dripping from the bottom corner of the radiator. I surrendered to what I was dreading and denying: the radiator must be leaking. At $600 for a new one, this brings us to the point in the journey where I decide to stick the bike into winter storage early and avoid the problem, at least until spring.
It’s been a pretty brutal winter here in Montreal. Finally spring came, I bought the new rad, installed it, rode one block and the temp light came on. Damn! Double damn!
I’m not going to say the rad wasn’t broken, because I think it was. It was bent from the tip-over and clearly leaking, or so my wallet says. So my problem is . . . shall we say, multifaceted. I little sleuthing on my favourite forum uncovered that the water pump on my bike tends to go at around 50-60,000 kilometres. My bike now has 63,000. I knew this before buying the rad, but because it’s quite an involved process to get to the pump, and because the rad was leaking, I thought it was a long-shot that the pump would go at the same time as the rad. But go it did. When I finally got the pump apart, which involved taking the clutch cover off, the gear that drives the impeller was stripped.
Believe it or not, I was actually happy to see this, for at least then I knew what the cause of my problem was.
How was I to know that both the radiator and the pump were broken? And the pump issue seems to be unrelated to the tip-over. There’s been an effort on the forum to try to get to the bottom of what’s causing the stripped gears but there doesn’t seem to be any consistency. For some guys, it happens out of the blue with no apparent cause; for others, it’s after a drop. My guess is that the impeller shaft gets worn and starts to wobble. Sometimes this results in the seals leaking, sometimes the gears stripping. At any rate, it seems to be the Achilles heel of this bike. Now I know.
With the bike back together again and all fluids replaced, I rode off and the temp light did not come on. Now I’m ready for another season and my journey can be of the real kind.
I enjoy working on the bike, or any kind of manual work, actually. Okay, sometimes there are frustrations, like when I couldn’t figure out how to get the clutch cover off with the oil return line in the way. But that too is just a matter of knowledge. I struggled for a while, then went on the forum and read that some guys loosen the exhaust manifold bolts just enough to drop the exhaust pipe out of the way. I’m looking forward to the time when I know this bike so well that the troubleshooting part will be a no-brainer and I’ll know the route before starting a job. Until then, patience and persistence are my travelling companions.
6 thoughts on “Double, Double Toil and Trouble”
Great piece, and you’re the only motorcycle guy in the world who, when explaining the motivation behind bike repairs, would quote Theodore Roethke.
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Thanks for the comment. I somehow missed it when you first posted. Roethke rocks! https://www.poetryfoundation.org/poems/43333/the-waking-56d2220f25315
Thanks for your trail-breaking! This is pure gold for a new owner and subscriber to Murphy’s Law.
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Keep an eye out at the weep-hole just under the water pump. If you see coolant leaking, it’s time to change the seals. If the bike overheats, remove the water pump cover, which is easy (not the whole clutch casing) and if you can spin the impeller by hand then your plastic gears inside are stripped. The good news is that I’ve done that job a few times now and it gets easier every time. And other than this well-known issue, the engine is solid! I’ve got 130,000 K on mine now and it’s showing no signs of age.
Thanks for the tip Kevin. I am much reassured by your experience which you so generously share. As a side note, my 05 thumper has 41K (valves clearances soon too I think) and started out life in Montreal.
I have some questions about torque wrenches. Do you have one? Can you recommend one? Or is “seat of the pants” the order of the day? My reintroduction to riding 8 years ago was on a VT600 Shadow (34HP) – about as mild-mannered as one can get, but a great knockoff of a Harley Sportster. I always intended to buy a torque wrench (or two) but never got beyond oil/filter changes before I sold it for health reasons.
I invested in two good torque wrenches when I started working on the bike. I like the reassurance of knowing that nothing is going to either fall off or break off. BTW, I put thread lock on pretty much everything.
I have a CDI 3/8 wrench (10-60 Nm) which I use for almost everything. CDI apparently make wrenches for Snap On but buying direct from the manufacturer saves you some money. If I remember correctly, I bought mine online from a distributor in the Toronto area.
I also bought a 1/2″ Mastercraft Maximum wrench from Canadian Tire. It is 20-250 ft/lbs but has a Nm scale on it too. I don’t know how good the quality of Mastercraft products are these days, but I’ve heard the Maximum line is pretty good, comparable to Craftsman of old. That may not be entirely true but the price was right (on sale) and I only use it for big stuff that the other wrench can’t do, like the rear wheel lug nuts.
Don’t forget to back off the wrench to zero after use for storage or you’ll damage the calibration. Sounds like you know that but many people don’t. Happy wrenching. I’ll be doing bodywork in the off-season—something new to me.