I found this BMW R100/7 sidecar rig on Kijiji in February 2025. The catch was that it was located in Montreal, about 3,000 km from home. Fortunately I have a good friend there who was able to pick it up and store it until I could fly out and get it. In June 2025 I flew to Montreal to finally meet the bike. My first ride on it was leaving the storage parking lot, and within seconds the handlebars started shaking violently at low speed. My first thought was, “Holy shit… I have to ride THIS all the way home?” Once I got a little speed the shaking went away. I later learned this is a common sidecar issue called headshake. Adjusting tire pressures, the steering damper, and suspension helped quite a bit, and I also learned that having weight in the sidecar mostly eliminates it. Before starting the ride home I spent a few days in Montreal and later stopped in Ottawa to visit friends. Early in the trip I ran into my first issue when the starter stopped working after a quick beer run. After looking at a wiring diagram and doing a few quick tests I traced the problem to a sticky neutral switch. I grounded the circuit and the starter worked again, though it meant the neutral light stayed on for the rest of the trip. A few blocks into the ride west I noticed fuel leaking from the gas cap. It turned out the cap had no seal at all. My temporary solution was stuffing a nitrile glove into the cap, which helped enough to keep going. Later in Ontario I discovered the right carburetor fuel line had split, but luck was on my side and there was a Canadian Tire only a few minutes away. With a short piece of new fuel line and my trusty Victorinox Swiss Army knife I was back on the road. The trip across northern Ontario and into Manitoba drew a lot of attention. Riding a sidecar across the country tends to start conversations wherever you stop. A loose battery cable caused a brief scare near Winnipeg, and I also managed to run out of fuel outside the city, but the 5 gallon fuel can I was carrying in the sidecar solved that problem. By the time I reached Moose Jaw I was only about an hour from home. Instead of heading straight back I made the questionable decision to continue on to Swift Current with plans to eventually get the bike inspected in Medicine Hat. That decision is where the trip finally caught up with me. In Swift Current the bike started once, then died as it warmed up and refused to restart. I tried new spark plugs, but that wasn’t the issue. With no trucks available at U-Haul I called my partner back in Assiniboia, who immediately jumped in my truck and drove out to rescue me. We managed to rent a trailer, but quickly discovered the sidecar rig was too wide to fit on it. Fortunately the small socket kit I had just bought at Canadian Tire had a 19 mm socket that fit the four mounting bolts. Off came the sidecar, the bike went in the trailer, and the sidecar was loaded beside it. A couple hours later we rolled into Assiniboia. After nearly making it across the country under its own power, the R100/7 sidecar rig was finally home. Now the real work of fixing it could begin.
Much work has gone into this bike since getting it home. This is my first Airhead and really my first major motorcycle project, so there has been a lot to learn along the way. The first job was rebuilding the carburetors. They were fully cleaned and rebuilt, but at the time it didn’t completely solve the running issues I was chasing. Knowing the carbs were now in good shape—and no longer part of the problem—I moved on to the next areas to investigate. While troubleshooting the engine, I discovered it had poor compression. Checking the valve clearances showed they were well out of adjustment. After setting the valves properly, compression returned and the bike started and ran much better. The bike was running at this point, but tuning it was difficult. When I checked the timing, I found it was off, and the old points system had a worn block that made it hard to keep timing consistent. Rather than continuing to fight with it, I decided to upgrade to a digital ignition. While I was at it, I refreshed the rest of the ignition and charging system for reliability. The bike now has a digital ignition, new diode board (basically BMW’s version of a rectifier), voltage regulator, coils, plug wires, plug caps, and plugs. With the ignition sorted out, dialing in the timing and tuning the bike became much easier and far more successful. With all of that work done, the bike was running great again. However, after some riding, it became clear that the valves were beginning to need adjustment more frequently than they should. That’s a classic sign of valve seat recession on Airheads of this era, so the proper long-term fix was to address the cylinder heads. The heads were sent out to Shail’s Motorcycles, a well-known BMW specialist, where new valve seats were cut and everything was brought back into proper spec. While they were there, the valves and related components were refreshed as well. With the heads completed, I went through the full top-end rebuild. The cylinders were deglazed, leaving a nice fresh crosshatch. The pistons were cleaned of carbon, new rings were installed, along with new gaskets and valve stem seals, and the freshly rebuilt heads were reinstalled. After setting the valves, the engine is now showing a healthy and even 145 psi of compression on both sides. The carburetors have been reinstalled, and the Seidenrock oil pan extension has now been installed. This increases the engine’s oil capacity, improving cooling and overall oil stability—both great upgrades for longevity—before refitting the exhaust. The tank, side panels, and fenders have been removed and sent to a very talented buddy of mine to be repainted in the original colors. I’m not usually an originality purist, but the factory paint scheme on this bike is just too good not to bring back properly. More updates to come as the project continues.
This Bike is bike is for sale, $1,000,000 firm. ;)
Bing Carb Rebuild! These were the first carbs I have ever rebuilt and were absolutely delightful to work on. They were pretty clean overall but the O-rings were hard and disinteg…
When I first got to investigating, the bike would barely start only when cold. I checked out the compression and the Left was "uhhhhhh ok?" and the right raised my eyebrow. A val…
Removing and disassembling the heads. Nothing alarming, a lot of carbon from running a little rich. This was after I had about 1000 kms on the rebuilt carbs and new ignition. I …
Removed tank, side panels, and fenders. I have sent these to my good buddy Steve in Calgary. He's got the skills to paint. I do not. I may give it a go on the Yellow bomber proj…
These are the pics from the shop that have completed the valve seats and valve cover refresh! From the pics I am quite happy with the work. They replaced the Seats/valve guides, …
Installed the oil expansion kit! This adds 1.3 Litres of capacity bringing it to 3.7-4 L
Browse the project-level images in one place.
Status: In Progress
Slug: 1978-r100-7-side-car
Created: March 14, 2026
Last updated: April 02, 2026
