I’ve been putting the kilometres on Bigby this summer. I’m now over 88,000 K and, to my knowledge (I’m 3rd owner), the rear suspension has never been serviced. I also had a small oil leak coming from the front of the engine, and I wanted to check that all the engine mounting bolts were torqued to spec. I hate doing maintenance during the riding season because I’ve lost the last month of the last two seasons waiting for parts, but I felt in this case, with three jobs needing to be done, I’d dive in.
This was the biggest job I’d ever done, as you can see from the photo above. The entire back half was removed. I mistakenly took off the fuel tank because I’d read you need to in order to reach one of the engine mounting bolts. Ha! As it turned out, that advice was referring to the 650 Classic, I believe, and in the end, it wasn’t necessary. But it also wasn’t that hard. I’d had the subframe lifted before, to get my shock off; the difference was just that all wiring had to be disconnected and the subframe bolts removed. I’d run the bike down to just a few litres of fuel, so my wife helped me lift the tank off. On this bike, the subframe remains attached and both are removed together.
With the tank off, I was able to access the suspension linkage easier. The deflection lever and tension struts (“dog bones”) came off easily enough.As usual, I took photos to ensure it all went back together the same way. But now the fun began. The pivot bolt that connects the swingarm to the frame was corroded inside and would not come out. It’s a big 12″ bolt that goes all the way through the bike from one side to the other. I checked the photo in my service manual; the guy is pulling it out with his fingers! Meanwhile, I whacked away with a hammer and drift but it wouldn’t budge.
I tried to get a bar clamp or C-clamp positioned to press it out, but could not get purchase with either; there was too much in the way. Finally I decided I had to lay the bike on its side, pour penetrating oil in the top end, and hope that it worked its way down to where the corrosion was.
No luck. I was beginning to feel like this guy who, after losing days trying to get his pivot bolt out, eventually cut the damn swingarm off! But I was not entirely out of options yet. I brought out the big boys: my dad’s old big ball-peen hammer and my sledgehammer. I flipped the ball-peen around to place the round end on the bolt, then, using it as a punch, hit the flat face with the sledge hammer. Slowly, slowly, the bolt surrendered, not to a higher intelligence, but a BFH!
With the swingarm off, I could see what the problem was. One of the bearings was seized. I guess this job was overdue.Of course my local BMW dealership didn’t have any of the needed parts in stock, so it was off to Vermont to pick up an order from MaxBMW. I love those guys! The parts took a week including shipping and came with their signature package of M&M’s included.
I’d never pressed bearings before and didn’t have a bearing press, but a YouTube video showed how you can use a common vice to do the job. You use two or three sockets on each end: one the same size as the bearing to press it out, and a bigger one on the receiving side to press the bearing into. You might need to add a socket on the press side to get the bearing fully out. With a little heat from a blow torch and a bar-clamp pipe as a cheater bar, it was easy. For some, I didn’t even use the heat. Just be sure to centre your press socket carefully to avoid damaging the wall of the swingarm or linkage.
I’d put the new bearings in the freezer overnight, so they had contracted and were easy to press in. A little heat helped but wasn’t necessary. Then I greased the whole thing up really well with the best waterproof grease I could find. My manual called for EP2 grease (Extreme Pressure).With the new bearings in, I turned my attention to the other jobs. A close inspection of the front of the engine indicated that the oil leak was not coming from either the starter motor O-ring or the clutch cover, as I had suspected, but the crankcase gasket. That’s the seam that runs the entire circumference of the crankcase front to back, holding the two halves together like a clamshell. My service manual indicated that the crankcase bolts are supposed to be 12 Nm, and two at the front were significantly below that spec. While I haven’t yet had the bike up to high revs, when the oil leak happens, I’m confident I’ve found the source. There were also a few other crankcase bolts further back in the engine that needed tightening.
Finally, the third job: the engine mounts. And here is where it became interesting again. I was missing one of the five bolts! Did I remove it earlier and lose it? I remember reading the specific instructions in my manual on where it is located and how it threads into the rear brake line bracket on the opposite side of the bike, but it’s not the kind of bolt one can lose; it’s M10 x 95mm. That’s a 9.5 cm long big bolt! Did I accidentally use it for one of the front engine mount bolts, which I removed to remove part of the frame? I searched the shed. I searched the workshop. I searched the grass in front of the shed. I searched my pockets, my tool bag, my car. I lost a day looking for that bolt, which had now become The Bolt and my wife was sick of hearing about it. To this day, I don’t know what happened to the 5th engine mount bolt. Fortunately, Canadian Tire had an M10 x 110 so I put that in. It’s a little long but will do the job until I get the proper one. Maybe it’s my imagination, but the bike seems less vibey, so perhaps one was missing all along??? Perhaps one day I’ll be cutting the grass and . . . gling! At any rate, I’m glad that all five engine mount bolts are in and torqued to the spec 41 Nm.Finally it was time to put the bike back together: the swingarm and linkage went on nicely, including the infamous pivot bolt, which I’d cleaned up and given a liberal amount of grease, including some anti-seize on the nut. Then the rear wheel and then . . . uh! I forgot the chain, so it was either break the chain or remove the swingarm again. I felt like an idiot over that one. That’s a mistake you only make once.
So I removed the swingarm, looped the chain over it, installed it again, plus the rear wheel, the mudguard, chain guide, rear rack, etc. until Bigby was looking himself again. And just in time. I have a reservation for two nights at Mew Lake Campground in Algonquin Park this weekend. I’ll be photographing the fall foliage and writing an article for Ontario Tourism on Highway 60 that winds through the park.
Mechanical work is hard! It’s not just the physical exertion but all the troubleshooting and decision-making involved. Two nights at a campfire with my pipe and some scotch is just what I need to unwind and close the touring season.