Restoring a 1973 BMW R75/5 Motorcycle

June 3, 2007

Death and Taxes

Filed under: airhead, BMW motorcycle, BMW R75/5, motorcycle restoration, R75/5 — Penforhire @ 7:38 pm

I took a vacation day Friday to get a jump on things, go to the DMV, buy more tools, stuff like that. Hence the illusion of massive progress in this post. Geez I really like puttering in the garage! We had another graduation party for Brian this weekend at the in-law parents’ house. This time the whole world was invited and most of Saturday was consumed with that. First time I’ve ever threw a party where we hired a serving wench. Now THAT felt pretentious (and I unsuccessfully argued we didn’t have room for another body in the house).

I learned how to tap a keg of beer. No, I never learned that valuable skill before. Anthony, one of my technical-minded brother-in-laws, and I went to examine the keg of Sam Adams, that nobody else had a clue about. He read the tag. It said to ask the distributor if you had any questions. I stepped up, Anthony took just the right number of steps back, and I promptly made a “beer fountain.” It was very cold and wet but, in hindsight, a really tasty fountain. Oh, so THAT’s the release for the piercing nozzle! Nobody had a camera handy but the fountain pic would have been a keeper. I smelled like beer for the day and that wasn’t all bad.

Here is what I was talking about in last blog entry, using feeler gages to load the damping rod into the fork.



If you do it right, and I didn’t at first, it won’t even mess up your feeler gages. Anyway, I picked 0.07 and 0.09 mm feelers. I don’t need those, right? 🙂

Here’s the finished punched VIN plate.


And yes, that is as evenly spaced as I could manage. You should see my hand writing. Got the punch set on sale at Harbor Freight for about $3. If you know what you’re buying that store rocks! Brad asked me a legitimate question, “is replacing that plate without prior authorization legal?” I believe it is because the frame and engine have permanent stamps separate from this plate, which seems to just be cosmetic. In this case all three stamps match but with motorcycles the DMV has a mechanism to track different engines versus frames. Must be a more common need than in cars?

Here are the new and old clutch plates.


This is the piece that gets sandwiched between the inner and outer pressure plates (those two are driven from the engine side, bolted to the crank). The central spline drives the transmission input shaft. The original lubricant specified for the splines is no longer available. As near as I can tell it went through at least three revisions. Here is the back of the tube of the latest-specified Microlube GL 261.


Spline lube is a big deal because of spline failures in BMW K-LT series bikes a few years back (in the Paralever if I recall correctly). Anyway, the reason I’m showing you the back of this $12 tube (Microlube doesn’t describe the price) is a small-world coincidence that a few readers at work will be amused by. This lube is made by Kluber, spelled with an umlat over the u, a German manufacturer of lubricants. Well, we had a big project at work that used one of their lubes and before that I had never heard of Kluber. Small world.

Here is me mounting the new clutch sandwich.


A few notes.

This would have been a huge pain the rear if I had to do it with the engine in place, like most folks do it. The early /5 assembly has spacers behind each bolt that would have been ugly to keep in place if I could not turn the whole thing toward the sky.

The silver thing in the center is a BMW clutch centering tool. The center of the clutch sandwich, the single plate I showed you above, is not kept in place by anything other than the clutch spring pressing the sandwich together until the transmission is mounted. Then the spline engagement keeps its position. So before the clutch spring is compressed absolutely nothing is keeping it in place. If you re-assemble without this centering tool you may have the plate too far out of position to engage the tranny splines. Here’s the thing. My new clutch plate has slightly larger diameter to the top of the spine teeth, as if the teeth are lower-profile. They engage the tranny splines tight like it should but that clutch centering tool is not quite as useful. I double checked with Joe’s tool and with my old clutch plate. The new plate opening is definitely larger and the centering tool has too much room to move. Anyone out there know anything about this? Post a comment!

Here’s the new & old clutch throw-out bearing and the grease seal for the rear-most clutch rod. The end of this rod is moved, through a pivot, by the clutch cable running to the handle on the handlebar.


Neither of the old parts looks too bad but I replaced them on principle.

Here’s another photo of the lower steering yoke. Probably one of my most repeated pics in this blog, eh?


That red arrow points to one of two features that nobody said anything about These are the answer to the fork gaitor question I had in the last post. There are two venting feedthroughs in the yoke. I just need to make a hole in the gaitor and slide them over these hollow posts. Why didn’t you tell me this earlier?

Well, we’re going to yack about this yoke a little longer. That lower bearing needs to come off so I figured I’d remove the shaft, as previously discussed. It is a tight press fit and temperature is required to loosen it. I believe a press was also mentioned. I already replaced the race this bearing rides on at the bottom of the steering tube. I didn’t take any pictures of me pounding it in and I was extra-dumb. I didn’t chill the race to make it easier to install. D’uh.

I took this picture, among others, to record how the shaft was positioned so I’d have so idea how to put it back.


If you muff up the rotation then the column lock will not work either. The lock cylinder slides into a slot in this shaft. Here was my idea for hot-and-cold on the parts.


That lower yoke is made of aluminum alloy and conducts heat really well. The entire yoke quickly became too hot to handle. The cold bag was intended to shrink the shaft as much as possible. Well, I either didn’t get enough temperature (120 C is the book recommendation) or the parts are otherwise corroded together. Nothing wanted to move.

Forced to give this some more thought, I had yet another head-slapping moment. I don’t need to remove this shaft. At all. I got the old race off by the prior technique of making two scores with a Dremel cut-off wheel and hitting one with a chisel. Cracked right open.

The book mentioned I should get the replacement bearing to 80 degrees C to ease its installation down the long yoke shaft. The middle section of the shaft is slightly small diameter than where the bearings go. The book also mentioned I should have a length of pipe ready to press the bearing in place if necessary. I measured everything and made some marks on paper to find the right pipe diameter. Good thing my life didn’t depend on my measurements because the 1″ iron pipe I came home with was, just barely, too small. I think I measured that smaller-ID section I mentioned. Bummer. Trudge back to the hardware store for a length of 1 1/4″ pipe. Yay, it fits! The ID doesn’t press on the I.D. of the bearing but rather the outer cage. Not ideal but better than nothing. I was smart enough not to try to place the bearing before having everything ready. I was taking no chances so I stuck the yoke in the freezer, just to be sure.

Well, when that magic moment came the hot bearing dropped to the bottom of the yoke like a stone in water. I didn’t need that pipe length at all. It was very anti-climactic. Here’s the new bearing on the shaft.


The bottom yoke is especially white because I got it so cold that frost formed on it! Maybe it doesn’t excite you but getting this job done was a big relief to me. Nearly a cause for celebration.

I mentioned I went to the DMV and that really set the tone for this post. I had not yet transferred the title into my name and my dad had last registered the bike in 2003. I figured I should not wait TOO long before seeing if I’d hit a snag in the beaurocracy. They say two things are certain in life, death and taxes. Well, the DMV is living proof of that. I had to pay back-registration fees or penalties (is there a difference?) of $360-odd (!) and fill out an Affidavit of Non-Use. I was expecting to submit a Planned Non-Operation since I’m months away from touching public roads but that would have saved me less than $20 and I’d have to go back to the DMV when I was operational (ugh!). So —


Yep, I’m street legal and a new pink slip is working its way through the bowels of the DMV. Now if I can only get roadworthy. I know this is the original license plate because I peeled off the annual stickers right down to a 1973 sticker! And did you know that the orange 2008 tag color is identical to the 2003 color? The DMV employee was very amused. I couldn’t wait to escape the building.

I bought replacement locks for the fork and seat because they were already not keyed alike. Unfortunately the replacement fork lock has a cylindrical lock section. Sh’yea? Not on a /5. Time to use the diamond grit Dremel tips I also got on sale at Harbor Freight.


This took longer than expected. Doesn’t everything? There are times when a lot seems to get done and there are other times when it feels like I’m pouring hours into it and not much happens. It doesn’t help that I was not too well organized when I took everything apart. I’d use more marked plastic baggies if I had it to do over again because I spend extra time on almost every assembly just locating the right parts. Sometimes quite a bit of time. I’m glad I’m not on a schedule. Did you ever watch the show “Build or Bust” on Speed channel (30 days for a non-pro to build a custom chopper)? I liked that show but I’m sure I would have busted. And they wouldn’t have let me anywhere near their tools.

I got the swing arm mounted. Here is one of the bearing races about to go into the swing arm pivot.


That bearing extractor tool of Ed Korn’s was every bit as useful in reinstallation as he said it would be. Here I am pounding the race flush to the swingarm a plate from his tool.


And then pound it to the bottom of the pivot using the plate turned vertical —


Grease up the whole bearing (I’m using some fancy red synthetic stuff everywhere Moly is not required), add the spacer, and press in new grease seals —


Mounting the swing arm to the frame is a little tricky. The gap to the frame needs to be the same on the left and right sides. You have to adjust two threaded mounting widgets to accomplish this. Only the movement is hard to understand and get right.

Here’s the right gap.


Here’s the left gap.


I used a caliper to verify my eyeball but the books don’t give the centering a tolerance. I got both gaps within 10 mils or so. The next steps are a little interesting too. You have to preload the bearings with a high force on the threaded widgets, then loosen and retighten to a lower force. You must have the proper torque wrench to do this work. Even that lower force causes what feels like too much binding to me. The bearings almost-but-not-quite keep the naked swingarm in place at any angle. Stiffer than I imagine desirable. Anyway, the last step is locking the threaded widgets with large outer nuts, the ones I had to grind a socket head to fit way back when. No wonder they were so hard to break loose. The spec is 100 N-M of torque! And you have to verify the threaded widgets didn’t move when you tighten those nuts, otherwise the torque will be incorrectly high on the bearings. Fortunately my widgets didn’t move. I’m not sure what you’re supposed to do if they DO move. Not as if you can hold them in place with a socket-and-torque-wrench already on the outer nut?

I bought a new center stand because of how rotted my old one was. Well, replacement part workmanship is not always perfect.


I had to grind one of the pivot holes slightly larger because the pivot spacer would not move freely in the hole. I would tighten the mounting bolts and the stand would get stuck in position. Both original spacers are the same diameter so this was a small flaw in the replacement part.

I titled this next photo “the creature takes shape.” It reminds me of a dinosaur going into a tar pit… or perhaps just the bones on display in a museum.


It is terribly exciting to see the form returning. The springs for both stands are tied to the motor mount bolts so I am spring-less until I mount the motor. Believe it or not, I am short one steering head bearing so I can’t go further assembling the front end until I get that ordered and delivered from NAPA Auto Parts. I expect all my wheel bearings to arrive this week, again from NAPA, about $25 each and only the unsealed design. Several sources indicate those are fine to use.

Oh, hey, I don’t think I mentioned it but I need those bearings because (yay!) I got the wheel parts and tires over to Buchanan Spoke and Rim! They are due back later this week. Picking them up during the week could be interesting. My wife managed to T-bone someone in a parking lot with her Jeep last Thursday so she’s borrowing my car while hers gets repaired. Good thing we’ve got most-excellent weather while I’m commuting on my FJR (keeps fingers crossed). But strapping two wheels-with-tires to the bike seems unlikely. I know Buchanan’s price list (you can see it on-line) but it still felt like sticker shock when they wrote up a $550 bill (I went for the polished stainless spokes & nipples)! Kids, if your wheels are in good shape take care of them! I don’t feel so bad about all that rim polishing work now. In case you’re wondering, because I sure was, the cost for new replica pre-laced rims is somewhere around $650-and-up each.

Since I don’t have the bearings (and other guts) in the wheel hubs Buchanan can’t balance them. This is good news/bad news. For about $100 I bought a wheel balancer with adapters for these wheels from Marc Parns. When I get to balancing them I’ll show you some photos of this trick bit of kit. Since shops want $25+ to balance a wheel I’ll break even after four wheels. Dynamic balancing on those fancy machines is, apparently, not necessary just faster. If I want to balance any other wheels I’ll need to spend another $50 on a set of universal cones for this balancer. The adapters I got slide into the hidden R75/5 bearings (inside the wheel hub).

Wait, I’m not done yet!

The speedometer is working its way toward Palo Alto Speedometer in a big brown truck. They need to evaluate it but they typical repair fee is around $300 for these. Man, the hits just keep on coming.

People have been asking about my total investment more frequently these days. I’m still in denial. I have a thick folder of receipts but I do not have a running tally. All I can tell you is Bryan was probably correct when he said, “you know your estimated budget? Double it.” He has the experience of doing a show-quality restoration-and-hot-rodding of a 1969 Camaro. Hmm, ’69… ’73… must be something in the water. I’m expecting to come in around $5K now. Maybe $1.5K of that is optional (e.g. charging upgrade, stainless-instead-of-chrome exhaust, electronic ignition, other unnecessary replacements). Over half is pure parts cost. So far I’m thinking/hoping repair services will be under $1.5K (heads, cylinders, speedo, wheel lace-and-true, rear drive teeth repair-TBD). I’ve decided not to crack open the tranny unless I have to. Paint and powerdercoat was $1100. Figure another $300 or so for rechroming some parts (TBD).

I’m sure I’m forgetting to tell you something else I did this week. I’ve been busy!



  1. Where can someone who needs one get their hands on one of those very useful bearing extractor tools?

    You’ve made excellent progress! I’m really trying to keep up. I’ve started making new replacement parts purchases 🙂

    Comment by David — June 5, 2007 @ 11:55 am

  2. See my link #9 in the “blogroll” list at the upper right. Cycle Works (Ed Korn) sells all sorts of these clever tools at reasonable prices.

    Comment by penforhire — June 5, 2007 @ 12:41 pm

  3. Im looking to get my 73 /5 frame checked to see if it is straight after a sidecar accident, you seem to be in socal, any suggestions or do you know any ‘gurus’?

    Comment by Rick — September 14, 2007 @ 9:18 pm

  4. Hi Rick. I haven’t used any such services but I’ve seen very positive Computrack reviews. See . They have a location listed in Corona (Race Tech).

    Comment by penforhire — September 15, 2007 @ 7:45 pm

  5. Hi,

    I want to repaint the frame on my 86 Honda and wish to remove the VIN plate to do so. Were you able to get your old VIN plate off without damaging it and how? Also, where did you get the nice new rivets to reinstall it?

    Comment by Vic — July 1, 2008 @ 6:48 am

  6. Hi Vic!

    No, I did damage my old plate slightly. I knew I wanted to replace it so I was not careful enough when I drilled out the old rivets.

    I believe I got both the rivets and replacement plate from Hucky’s because someone else suggested them(see Note these are not really rivets but rather an odd press-fit stud.

    Comment by penforhire — July 2, 2008 @ 8:32 am

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