 |
As work progresses, the work table becomes
more and more cluttered with parts and tools. No matter what the job,
it seems that on every work table in the shop, one eventually sees: a
quart of oil, a can of grease, a can of WD40, a spray can of Kroil oil
to loosen rusted parts, and a spray can of carb cleaner. Vech is a
fanatic about carb cleaner. He uses it to degrease small parts and to
degrease surfaces before he applies gasket sealant. I estimate that we
use about 24 cans of it over the course of a restoration project. I
estimate about 50 shop rags are used per restoration project. On the front of the engine, the brown item with wires is the distributor cap. The silver-colored canister item to the left of the distributor cap is the new coil. The R51/2 has a battery ignition. Underneath the generator cover, Vech replaced the original mechanical voltage regulator with an electronic regulator, because the electronic one does a much better job of regulation. Just beneath the handlebars, you see the original BMW identification plate. Originally, the plate was printed in black paint, but with age, this one has faded to brown. We could replace the identification plate with a reproduction, but we condsider the original plate, although browned with age, a "badge of honor." The identification plate must be mounted before the headlight, otherwise it's just about impossible to reach the identification plate screws. |
 |
Remember that Volkswageon lug bolt someone forced into the rear end? Vech repaired that. Vech also had to repair the stripped threads of the transmission drain. Andy Hodnett welded the hole shut. Vech used a drill and a tap to re-thread the hole to accept the correct magnetic drain plug. |
 |
Vech heated the transmission case and installed the brass bearing holder of the input shaft. There are many places on a R51/2 that utilize heat-shrink-fit: engine rear main bearing, transmission shaft bearings, final drive bearings. I consider it a pure sign of BMW quality and engineering. Their obsession with precision fit probably stems from the days BMW produced aircraft engines. Vech said he doesn't know of any other vintage motorcycle brand that has such close machine tolerances. |
 |
We had a shop visitor who works on many other brands of vintage motorcycles. He examined the BMW R51/2 restoration progress. We had one piston and cylinder installed on the engine and no head. The visitor tried to wiggle the piston in the bore. He said, "My God! You don't have any clearance!" Vech explained that, when new, vintage BMW motorcycles have a .0025-inch piston-to-cylinder-wall clearance. When you try to wiggle the piston side to side within the cylinder, .0025-inch isn't enough to feel. The shop visitor was suitably impressed, while I beamed with pride in my BMW motorcycle. |
  |
Front fork assembly: the lower spring seat, the seal, the upper slider bushing, and the lower slider bushing (in hand). Next came the circlip to retain the bushing. The lower photo shows Vech as he installed the fork into the upper and lower triple clamp. The lower sheet metal spring cover was wrapped with a layer of paper to prevent scratching the paint job during installation. After the fork was installed on the bike, Vech loosened the tappered upper spring cover and installed thin paper shims to ensure that the upper cover was centered around the lower cover to keep the two from rubbing together during operation. Only then did he remove the paper protection ring. |
 | Special tools The left photo shows a bearing splitter and harmonic puller to remove the front bearing from the input shaft of the transmission. The second photo shows a special KIKKO brand, German, inside race puller that removes the rear input shaft bearing from the brass holder. |
 |
Christmas,
2001 -- a few of my favorite things: my hubby, my bike and my son,
John. It's a big day in the shop. Time to install the transmission. The
first time Vech tried to put the transmission in place, it just
wouldn't fit, no matter how he maneuvered it. Rather than force the
transmission into place, Vech removed it. He examined the engine studs
and saw that they were bent. When he "double-nutted" the studs to
remove them, it was very obvious the studs were bent. They wobbled as
he turned and removed them. He installed straight, new stainless steel
studs. Vech protected the frame paint with shop rags. Then, he and John lifted the transmission into place. The transmission slid right into place, without a problem. They tightened the bolts and tested the foot shift as well as the hand shift. Both shift methods caused the transmission to smoothly go through the gears. It looked as if the transmission works fine. It's pretty neat to watch the two shift methods work. Use the foot shift lever and the hand shift lever moves in unison. Use the hand shift lever and the transmission shifts, but the footshift lever doesn't move. |
In the shop, Vech sometimes beats the heck out of things with hammers, punches, etc.. Other times, he treats parts as gently as he would a newborn babe. I asked him how he determines his "shop force strategy." He explained that the amount of force he uses is determined by the metal type and characteristics of that metal, such as composition and hardness of the metal. He said aluminum can be fragile. When he works with engine and transmission cases, he is careful not to bang around too much. When he tightens a bolt, he can tell from the "feel" whether the threads of the case or the threads of the bolt are dirty or damaged. If the threads are dirty or damaged, he removes the bolt and uses a tap and die to clean and repair the threads before he puts the bolt in again. He uses the least effort possible to keep from breaking anything or damaging the aluminum threads in the case. When I thought about metal hardness, I realized how handy Vech's brass hammer can be. When he uses the brass hammer on steel, the brass head "gives" before it can damage the steel part. Hardness is also a consideration when Vech uses a rubber mallet on fragile items such as plastic, chrome, aluminum and brass.
 |
Back To Restorations BMW R51/2 journal, page 1 BMW R51/2 journal, page 2 BMW R51/2 journal, page 3 BMW R51/2 journal, page 4 BMW R51/2 journal, page 5 BMW R51/2 journal, page 6 |