Part 3 - Getting Down to the Basics

First we need to wrap up stripping the frame down. I remove the wiring harness and decapitate the headlight bucket. I'm happy to remove the hideous after market universal mirrors...they won't be back. I notice they stripped all the paint off the controls, which is not stock, not sure why they did that. I notice some pieces missing on the throttle controls that keep them tight on the handle bars...we'll have to replace them. This is one really ugly set of handlebars, finally coming off the bike. I move to take off the wheel and see there's quite a nice axle. Time to belt down the bike to stabilize things and place a block of wood under the stand to tilt the bike up. It makes getting the tires off much easier. There's a lot of grumbling going around BMW circles about appropriateness of chrome accessories. These axles and fasteners look like they came from a dealer, very high quality. With the tires off I go back to finish off the front end...the mystery question being are there ball bearings inside or did somebody put some tapered head bearings in here. Drum roll.... roller bearings!

Sidecar Lugs Coming Off

After we have everything basically stripped down and just the frame is left...we still have the problem of the special sidecar lugs that were welded onto the frame. In order to restore the bike to its original U.S. front end, we need to get these lugs off. I put on my goggles, tip the frame on end, and get to work with a rotary saw. I saw, and saw, and saw some more, sparks flying, bang a bit with the mallet, saw, saw, saw, saw some more, until they finally give way. We'll send the frame over to our metal guy for some clean up, and then it will be ready for powder coating.

Transmission Demolition

I begin with the output shaft. I have a special flange puller tool that will help me pull. I try to pull it but need more leverage, so I get a longer handle. It continues to fight me, so I get the pneumatic drill to help me out, and it finally pops off with the help of a rubber mallet. As I remove the output flange, I notice it has a tapered fit instead of a key. This helps it stay on there really tight and not slip.

I start to take off the nuts on the rear cover. I apply heat with the torch to allow the bearings to release more readily. I heat some more and tap gently upward, but have to resort to a screw driver to tenderly pry it up. I don't want to bang up the mating surfaces and cause any potential leaks. As I tilt it, I get an unpleasant surprise learning that there is still oil inside that needs to drain. As I empty it, the clutch push rod falls out...it's broken. It's a common break, we'll get a new one. I have to fish the shims out of the oil and clean them off. The drain plug is magnetic, so bits of metal will collect on it. I remove it and find it "furry" with some bits of metal on it, which is common for a bike of this age. I apply heat to the back of the case and attempt to remove the shafts.I have someone hold down the case while I use a special tool to pull them out. Finally they give. The first gear looks fine and the spline looks nice. There's no water damage from the bike sitting, which is a good sign. Sometimes water drains down the boot on the speedometer when it goes bad. Water can cause the bearings and gears to oxidize. Now, on to the final drive.

Final Drive Tear Down

We'll be bead blasting the outer case, replacing the seals, gaskets, and check the bearings out. I unscrew the final drive from the wheel. It used to be the tires on BMW's both came with hubs, so if the spines wore in one, you could rotate them. Looks like there is gasket sealant, so it has been worked on before. The inner case is popped by screwing in a 6 millimeter tool into the holes. BMW obviously thought of making maintenance easier this way. I remove the parts then heat the casing to get the needle bearing to drop out. I then fish out the gasket and the pinion. I'll put them in the parts cleaner and then they will be sent off for bead blasting. At this point the bike is entirely apart, and once we have all the parts we need for each system we can begin reassembly.

Parts, Parts, Parts

One of the greatest challenges to getting a bike restored is finding all the correct parts. In our case, we have the added challenge of building it in about half the time we normally have allotted. Some parts can be restored, others must be replaced with new reproduction parts. We have a team of experts we work with to outsource many of our more specialized needs. Some of this we could do ourselves, but in the interest of time, we turn to the people we know who can get the job done quickly and with the best results. Check out the master plan (link to master plan page, use standard link color) for the restoration, and find out the true challenges of a restoration.

Let's Put It All Back Together

The engine parts have all been cleaned, and we're ready for reassembly. The parts are pristine and laid out on my workbench like a surgeon's instruments ready for work. It's time to get down to business. The hardest part about rebuilding an engine is making sure to set the bearings correctly in the crankshaft, so they are moving freely in the block. I start by putting in the rear bearing carrier after heating the torch to make it easier to work with. Next I take the very beautiful, much loved crankshaft and place the slingers on it. The slingers catch all the metal particles and other gunk over time, so they have to be cleaned about every 30,000 miles.

Next I put on the spacers, and take care to add some talo from Ed Korn onto the bearing surface to lock it in place.

With the heavy flywheels these bike use, you get a lot of flexing of the crankshaft, so with the flexing they were getting bearing failures. I've never had much trouble, so we're going to stick with what we've got. Once I have the crankshaft in place, I use a special rear bearing alignment tool, to get things perfect. Next comes the timing gear, and then the cam shaft, and the oil pump gear. Finally it's all coming back together.

Final Drive Nightmare

It's a bright sunny day in the shop, and I'm attempting to reassemble the final drive. As I begin to assemble it, I attempt to seat the inner pinion bearing and Houston, we have a problem. I have split the casting. Not sure if we can weld it without messing up the entire housing. We'll send it off to Ray-Ray our machinist, to see if he can fix it. It wouldn't be a restoration if something didn't break. Hopefully we can get it back in time for the auction.