Part 2 - The Sidecar - to be or not to be?

After some hemming and hawing, and considering the future of the bike, its destiny to be auctioned for charity, etc... we decided we just have to return this bike to its original glory with a U.S. front end. The BMW R69US was never meant to have a sidecar attached. Whoever attached it went to so much trouble to get the sidecar lugs put on, that getting them off is definitely going to be a challenge. They also put on an Earls fork, while appropriate for the addition of the sidecar, does not fit with the U.S. model. It's a miracle they were even able to pull a sidecar with the bike. If it weren't for the 27/8 final drive ratio, which made these bikes faster off the line, it wouldn't have had the power to pull the sidecar. So without further ado, I begin the process of removing the sidecar. With some amount of trouble, I'm finally able to pull the side car off...like the parting of the Red Sea...the sidecar is off, and it's like we have a whole different bike.

Next off is the fairing...a common feature for touring bikes in the 60's. I try to keep all the original fasteners with the fairing. Next we remove the saddle bags. They aren't right for the bike, but they're high quality Enduro bags, which can fetch a pretty penny on Ebay. All rubber straps will have to be replaced.

Fuel Tank Treasures

I'm dying to find out what's behind the knee pad on the fuel tank. I've got to remove the tank, and I'm hoping there isn't any old gas in it. Old gasoline can be quite toxic, so I put on gloves during this part. We don't have a key for the cap, so we're gonna have to break into it. I finally have to drill the cap off. The cap isn't completely destroyed, and it is an original BMW accessory. The gas inside is old and smells sweet and varnish-like. I use a hose and some air pressure to drain the tank before removing the tank completely from the bike. There were traditionally two sized fuel tanks for these bikes, a six gallon, and a 4.3 gallon, which significantly changed the look of the bike. As I remove the fasteners to the fuel tank, I remember there are two choices. You can have originals re-plated, or you can replace with stainless, which is what we're going to do in the interest of time. I realize we're going to have to cut the cross over to get the tank off.

I like a lot of things on this bike, but some of the parts aren't original, so we're going to have to find the original parts...like the air cleaner. As I'm lifting the empty tank off the bike I get excited...it has a lot of weight to it considering it's empty. Could this mean there is still an original BMW tool kit inside the glove compartment/knee pad? Since I don't have the key, I have to cut the old rubber and drill out the rivets. I carefully use a center punch to create guide holes for the drill. One slip off and it can damage the tank. I put on safety goggles to protect against the flying metal shavings. I pull away the cover from around the lock and reveal...an original tool kit wrapped in a leather pouch. The tools were specially made by BMW to help service the bike along the road side if necessary. It wasn't uncommon for people to work on their own bikes back then.

Engine Demo

I am going to remove the engine now for disassembly. First I remove the clutch thrust shaft. It's worn and will need to be replaced. After undoing all the fasteners for the engine, with help, I lift the engine up to a custom BMW engine stand. We secure it and I begin working. Part of this might be difficult, as the cylinder flanges stick up into the heads and get locked in there with carbon build up. Never know though, they might just come right off. To my surprise the valve covers come off with relative ease and now I can get to the head bolts. This was the largest engine in its particular BMW series. They were good performers. The heads come off easily, no broken/bent fins on the first one, no real valve recession. The other side does have a couple bent/broken fins. We'll have to have them repaired on that cylinder. We think the person boring the cylinders can handle the repairs.

Next I tackle the clutch. Taking a hammer and screw driver, I mark the pressure plate, so I can remember what position it was in. Be careful not to breathe in the dust when working on the clutch plate. After marking the plate, I apply special screws to help take pressure off gradually from the diaphragm spring. The special screws are part of a set of tools I found especially for dealing with bikes from the 5 - 7 series.

I go back to working on the cylinders, and see that the previous owners chose to add a thicker base gasket, a common practice to help lower compression. At this point, I discover that the engine at some point was overstressed, got overheated and started to gall the piston. The cylinders and pistons will definitely need to be replaced, and possibly go up a size. I finish removing the pistons. I have to use a torch to help get the rest pin to slip out easier. The bike wouldn't have run well for long with the pistons so scored up. There's a pretty late flywheel with a thicker center web. On the very last of the /2 series engines, the center web is thicker providing for a heavier duty crank shaft.

Someone loved this crank shaft a lot, had some special balancing done. I pull out the cam followers and all four look to be in good shape. After the cam followers are out, I use a 5 mm allen to remove the cover of the oil pump drive gear. There is a special assembly there for the tachometer that could be added as an upgrade in the rebuilding of the bike. The seals are dried and old, time to be replaced. I use my Ed Korn many in one tool to help remove the front timing cover. I apply heat with the torch to help expand the case and release the bearing. The shutter plate was redesigned to have forged fingers instead of pins, to keep the timing gears from breaking down. The earlier engines had cast iron front bearing carriers, but this one has a nice aluminum one, which is better because it allows for expansion. The bike has a plus 2 set of timing gears, which tells us how they are sized. It isn't uncommon to find different sized gears in a case, because the centers do adjust over time with wear and expansion of the engine cases.

Finally I'm at the oil pump gear, which has a reverse thread. I pull the bolts out of the cam shaft, and with a tap on the impact driver, they come loose. Using a special crank shaft pulling tool, I remove the flywheel. After taking off the flywheel, I pull of the front crank shaft gear along with the alternator bearing. Both the gear sets look pretty good and should last the life of the bike. I put the pulling tool back on and apply heat to the casing to make removal go more smoothly. Gently I remove the oil slingers...they don't look like they have a lot of build up on them...so some engine work's been done not too long ago. As I remove the crank, I notice a thicker center web. It's a truly gorgeous crankshaft. It bears a stamp of 1974, proving the engine had some later wok on it. Everything looks professionally done, and I move to the last step of removing the Bowman oil pan. There's a lot of remaining silicone "goop" leftover from the previous job. I don't recommend using it, as it can clog the oil feeds. After the oil pan is removed....the engine is totally dismantled and ready for cleaning.