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jklearman
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Friends, I own a '39 BMW R61. Everything matches, is original, etc. It is my understanding the bike has some rare pieces on it, notably the original very large bell/flared fender on the front wheel. I was able to start the bike last year and ride it. The bike rolled off the assembly line on September 9 '39, the same day Germany invaded Poland, which I thought was interesting. I have confirmed this with Mobile Heritage, along with the original dealer and any other history I could drum up. It was brought over by a US soldier, the original owner, in the early 40's.

I'm tearing the bike down to restore it (I'll post some photos soon if desired and at various stages). I'll do whatever I can do myself, and I'll let subject experts handle the things I can't - which may be reasonable chunks.

I have the bike almost completely disassembled except for crankshaft and transmission removal. Cases are separated. I have the clutch and flywheel off and access to the crankcase.

Does anyone have any images related to removing the crankshaft from the case for a pre war R51 or R71 (or R61 for that matter)? This case is one piece on mine so my understanding is the crankshaft will come out the rear. I've been informed to remove the rear bearing, then press out (push toward the back) the front bearing. The crankshaft will "drop" and then I will need to find the correct position to remove it. I'm trying to understand the small puzzle here. I'm not seeing a few things - where to put a pull tool on the rear bearing for instance, or where to press the front. I can make a tool if need be, or buy Ed Korn's if appropriate.

Any thoughts appreciated. I'm happy to share the process as I go along - if anyone cares. It is evident I'll need some opinions and advice. This is the first motorcycle restoration I've done - translated ... I'm green but not intimidated (maybe kidding myself).

All the Best,

John

Darryl.Richman
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Surf City, USA (Santa Cruz, CA)
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1939 BMW R61 Project

I have not worked on this generation of motors, so I have no first hand experience here. In general, when there's a place where aluminum is holding something steel, BMW will have used heat to put it together, and you should use heat to take it apart.

The R5/R51 motor is different from the R6/R61/R66/R71 motors. The former has dual camshafts and a wider crankcase; the latter, a single cam and narrower case.

I have seen that the prewar motors have a large bearing carrier for the rear main bearing, so perhaps the crank does come out the back.

I would guess that if you heat the case to about 300F, you'll easily be able to remove the rear carrier without a puller and then pull the crank backwards from the front carrier. Once the crank is out, you can use one or another method for removing the bearings themselves.

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jklearman
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R61 Crankshaft

I've included a link below to some images of the front and rear of the crankshaft. The R61 case doesn't split open like some of the later models. The images show a front bearing flush with the housing / carrier (if my terminology is correct) (so no way to pull it out, only to push it towards the rear presumably). Again, if my terminology is correct, there is no way to simply remove the front carrier. It is part of the crankcase. I've shown two moderate sized holes, one below left, the other above right, in the front housing. I wonder if they are there to provide access to the front portion of the crankshaft (and there are two little holes on that front piece that I've highlighted). The rear is much the same, except if I chose I could clearly remove or pull the rear bearing. I don't see any need to do that though, as it should just come out with the crankshaft.

It appears as if the crankshaft is "suspended" simply by the front bearing sitting in the carrier, so that if I pushed it back the crankshaft would simply be loose.

I spoke with Vech about this and he didn't indicate heat was required. Although, upon inspection, if the crankshaft is simply suspended in the front by the bearing (does that make sense) I could use heat to loosen and push back.

Vech indicated that two 8mm holes were in a carrier near the rear of the crankshaft, and if I understood correctly I could put to small bolts in there and pull back. I think the confusion here is that there is a component (not pictured) that I removed from the rear of the crankcase that does have two holes for 8mm bolts. But it was attached to the crankcase, so pulling back on that would have no effect on removing the crankshaft - hence I removed it for access to the crankshaft from the rear.

Thanks in advance for any additional thoughts.

http://www.flickr.com/photos/21070070@N02/sets/72157603399773092/detail/

Darryl.Richman
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Surf City, USA (Santa Cruz, CA)
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1939 BMW R61 Project

Great photos!

I hope Bruce Frey or Peter Nettesheim happens along, they will certainly have direct experience with this.

If you don't have a parts manual for this bike, you should get one. You can find one on line here, at the BeemerGarage site: http://www.beemergarage.com/manuals.html

The piece you removed from the rear of the crankcase is the rear bearing carrier. It's aluminum, right? Was it a tight fit on the outer main bearing race? I would expect it to be tight, and just pulling it off would not be my favorite way of doing it. Rather, I would have removed the screw securing it to the tunnel crankcase and then heated it with a propane torch before removing it.

On later motors, the crank comes out the front and there's a small carrier in back that should be an interference fit without heat. When it is no longer an interference fit, it needs to be replaced.

The two holes you note on the rear crank web were made by BMW when they dynamically balanced the crank.

You will need to remove the "quill" shaft, which runs from the camshaft down into the sump to drive the oil pump, before you can remove the crank. You can see this shaft passing behind the left side of the crank in the last three photos.

There's a cover, #113 on page 7, on top of the crankcase that you need to remove. (These covers don't need to be torqued particularly tight, but everyone always does, and then they're a PITA to remove.) Under the cover is the top of the quill shaft and a helical gear that meshes with a worm drive on the cam. Pull it out with a pair of pliers. The main part of the shaft has a square cross section, and the bottom fits into the pump to drive it.

From the drawings in the manual, I can see that the machined area around the front main bearing, which you are taking to be a part of the casting, is in fact a separate, steel piece (#4 on page 6). It, along with the front cover that you've already removed (#42), capture the front main bearing and keep it positively located, while the rear carrier (#2) allows the rear bearing to "float" a bit.

The front bearing has to come off the front of the crank before it can be removed out the back. On the later bikes, you need a specialized tool to pull both the carrier and the bearing. This tool works by locating a bar across the nose of the crank with two screws that thread into holes in the carrier on opposite sides. The bar has a threaded hole that centers over the crank nose, and a pusher is threaded into this to apply pressure to the crank nose. (I have used Ed Korn's tool for this and it comes with a cap screw to thread into the crank nose, which takes the direct pressure from the pusher, so as to protect the crank itself.)

When the crank is free, you can heat the front of the case, and the steel carrier should be easily removed.

Please get some more advice regarding the front bearing and carrier before proceeding. There may be some other details that are important here!

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jklearman
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1939 BMW R61 Project

Thanks so much Darryl. I do have a parts manual and I should have referred to it for this exercise. I would have seen my mistake in thinking the steel piece is part of the casting. Also, you are correct that the piece I removed from the rear is aluminum and it was a moderately tight fit although came off without too much resistance using a pulling tool. It had two unused threaded holes into which I inserted bolts to which I attached the puller.

I exchanged an email with Richard Sheckler this morning who wrote:

"You will need to heat the case to about 250-300 degrees F. The oven in the kitchen works well for this. You'll need a pair of welder's gloves, a piece of plywood for the kitchen floor and your wife's permission!

Then remove the oil pump drive. Unscrew the large 2.5 inch diameter cover on the top left rear of the engine case. The oil pump drive can be pulled up and out from there. Next, remove the camshaft.

With a plastic hammer, tap the nose of the crankshaft in order to drive it aft. Once free, it will be able to be removed from the large opening in the rear of the case."

Combining perspectives I should be able to get this done - with my wife's permission as Richard indicates.

Many thanks!

John

Darryl.Richman
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1939 BMW R61 Project

That's great, Richard would definitely know the right thing to do here, he has a lot of experience with these bikes. One day I'll have a prewar plunger bike...

Good luck with your dismantling. Be sure to take more photos. You can't take too many, as a matter of fact. Be sure to get photos of each shim and which way it goes on. You will want these photos later, trust me!

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jklearman
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Photos

I have many many photos at various stages of dismantling. Sometime within the next day I'll put them on Flickr or post directly here (if I can figure out how to do that).

At some point soon I'll begin restoration activities.

All the Best,

John

jklearman
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History

I was surprised nobody called me out on my date error. Germany invaded Poland on Sept. 1 1939, not Sept. 9 as per my original post.

For me, part of the fascination with these bikes is their linkage to history.

I hope to have at a minimum a link to a website with a bunch of photos of the R61 within a day or two.

Regards,

John

Bruce Frey
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Texas Hill Country, USA
Joined: 10/27/2006
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1939 BMW R61 Project

I have been on the road for a few days, but you have good advice from Richard and Darryl.

I don't think you need to heat to remove the oil pump shaft (although removing the shaft cover was one of the hardest things I have done to my R71......this was one of those cases where the bike spent time on the Eastern Front and the only tools the PO used were a hammer and chisel).

The front bearing carrier is not the sturdiest piece in the world and mine had been chewed on by an ill fitting front slinger, so heat will probably make removing the front bearing from the crank a bit easier, thus minimizing stress on the carrier.

If you give me your mailing address (you can PM me if you prefer) I will send you a CD that has an English language handbook and some other interesting bits.

Ciao,

Bruce

jklearman
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1939 BMW R61 Project

Thanks Bruce. I used a torch to heat the area around the bearing, took a rubber mallet and a few taps later the crankshaft was loose. It was much easier than I thought it would be and I didn't have to bake the crankcase with dinner (which made my better half happy).

The only play I can discern in the crankshaft is a very tiny bit of fore aft movement at the piston rods, but none elsewhere. My current understanding is that the tiny fore aft play is acceptable and part of the rod assembly. I will do some measurements with a micrometer asap to see if I notice anything else. The BMW markings and etchings are visible. To the eye it appears in good shape, although I understand measuring is the only way to discern its true condition.

I'm off tomorrow to purchase some items to clean parts and possibly a small blasting cabinet for cleaning activity. I'm all ears if someone has suggestions here.

I hope to have images up asap on the bike and the dismantling I've been doing.

I'll PM my address, and thanks for the offer.

John

jklearman
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Images of the R61

Friends,

Link enclosed to a few images of the R61 and pieces.

John

http://www.flickr.com/photos/21070070@N02/sets/72157603437952557/detail/

Barry Robin
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San Francisco, Ca.
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1939 BMW R61 Project

john, unless i'm going crazy, the front fender is from a postwar R51/3 or R67; the valance is too deep for the prewar originals which still had the elephant ear back but had almost no side valances. same with the pinstripping: the prewar, if i remember corectly, had it's stripes following the curve of the wheel instead of going straight accross.

-barry

jklearman
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Fender

Barry, that may be correct. I honestly don't know. According to Richard Sheckler it is original but pre-war. I will probe Richard with your thoughts on that.

John

Darryl.Richman
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1939 BMW R61 Project

Barry, I would have agreed with you about the fender. Certainly, the R5/6/51 all came with the unvalenced fender you're thinking of.

However, the book I referenced over in the JN3 thread, BMW Fotoalbum 1923-1969, has a number of photos of R61s. Some have the unvalenced fender; but more of them show a valenced fender, and it's not just bikes delivered to the military.

One thing that may distinguish the prewar fender from the postwar "elephant ear" fender is the tabs for a pedestrian slicer license plate. The prewar photos all show those tabs, and the postwar bikes never had a provision for them.

So far as I can see from your photos, John, it looks like you've got a real treasure there!

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Bruce Frey
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1939 BMW R61 Project

If you scroll through the BMW Archive photos, there are a couple of WWII pix of a an R61 with a deep valanced fender, so it does exist.

I would need to do a side by side comparison to tell the difference between the prewar and postwar deep valance fenders, however. There is also a Russian version that looks very similar.

Ciao,

Bruce

jklearman
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Fender

Richard indicates the following:

"The fender you showed me some time ago is pre-war. Look for the rear casting riveted to the back of the fender above the bell. If it is on the outside where the front kippstaender tab can mount, your fender is pre-war. If riveted on the inside of the fender, it is post war.

BMW manufactured several front fenders for the R5 through R71. Two of them were deep valenced and one shallow. When the deep ones were pinstriped, the stripes followed the contour of the wheel as they would with the later R51/3 and R67 models. The shallow fenders were not pin striped."

I double checked and the casting to which Richard refers is located on the outside of my fender. I'll see if I have an image of that and put it out there in the flickr archive.

Regards,

John

jklearman
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Additional Fender Image

I posted an additional image of the rear of the fender here:

http://www.flickr.com/photos/21070070@N02/2105026261/in/set-721576034379...

I knew if I began talking about this bike in a public forum I was "opening myself up". I say that in a positive way. I have learning to do. Though being a somewhat private person it made me nervous. But let me disclose an additional item about this bike. Something I've struggled with. If you look closely at the photos of the frame you'll notice welds on it. My current understanding is that a number of pre-war bikes purchased by military personnel were shipped back to the States when the war was heating up. The US Military had fixed sized shipping containers - smaller than a motorcycle. And the US Military also paid for any shipments back. So, there are a few examples , from my understanding, of soldiers cutting BMW bikes and then welding them back together when they got them back home. There seems to be two opposing thoughts on how to handle this. I'm still contemplating my approach to restoration, although I do have a leaning that I won't disclose here (for the moment). One school is to ensure the frame is straight and to clean up the welds. The other is to ensure the frame is straight and not touch the welds - as they are indicative of the history and story of this bike. While post restoration value is important to me there are certainly other drivers in my decision making.

Regards,

John

Barry Robin
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1939 BMW R61 Project

sorry if i opened up a can of worms there, john. as darryl pointed out, if it's indeed prewar you do have a real find.

at least i didn't point out the incorrect R51/2 gas tank kneepads that i recall should have no patterning other than an overall diamond-shaped cross pattern...but that should be an easy fix...

-barry

jklearman
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1939 BMW R61 Project

Barry, not at all. I have lots of learning to do and appreciate the discussion. I had also seen the kneepad difference - it was one of my early removal tasks. I think I need new rubber pieces just about everywhere. I can also point out the incorrect chrome piece above the air intake. Another easy fix.

Bruce Frey
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Texas Hill Country, USA
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1939 BMW R61 Project

With respect to your frame, be suspicious of the quality of the welds. My R71 frame (which was bent) had some welds that sound similar to yours. When they put it on the frame table and started the straightening process, the welds quickly broke.

Have the welds checked out by someone who knows what they are doing if you decide to leave them.

Ciao,

Bruce

jklearman
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Additional Images of R61

Friends,

I've put a website out there with images of various aspects of the project. Most of the photos are in the "Image Library". You'll find the website at:

http://www.r61restoration.com

Many images and disassembly steps are still missing, but I'll have them out there in the coming days. The bike is very much in pieces. Now that I've put it out there I'm under self imposed pressure to make some progress. :shock:

Happy Holidays,

John

jklearman
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Posts: 15
R61 Wheel Restoration

While trudging along, I was able to get the wheel restoration process finished. If you wish to know who did it PM me and I'm happy to pass along the name. It took the better part of 6 months but I'm pleased with the result. I'll have to hunt down a shot or two of the original wheels, but you can see some snaps of the restored wheels here:

http://www.flickr.com/photos/21070070@N02/sets/72157603399773092/

The frame straightening process begins within the next two weeks. I'm simultaneously working on some engine matters.

Best Regards,

John

www.r61restoration.com

jklearman
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San Diego
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Posts: 15
Old Wheels / New Wheels

I've put some images of the pre-restoration wheels out there. The restored wheels are using Buchanan stainless spokes and they are not powder coated. The original spokes couldn't be salvaged as you might surmise, and that can also be noted in the photos. The original wheels weren't powder coated (of course) and therefore I chose not to do it here - nor will I anywhere else on the bike. I used PPG Black thinly and carefully applied and a PPG middle toned silver for the middle section of the rim. All of the original bearings were fine and were simply repacked.

http://www.flickr.com/photos/21070070@N02/sets/72157603399773092/

John

www.r61restoration.com

jklearman
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Posts: 15
R61 Status

Friends, I've received emails lately asking about the status of my R61. I've been busy working so haven't made much new progress. That said, my friend, Tim Stafford, of TJ Scoots in San Diego, has agreed to aid in the restoration process of the R61. As many of you know Tim is a preeminent restorer of old BMWs. I own one of his Dover White R50s and it is an exemplary piece. I'll try to periodically put some updates out here and on the site.

Kind Regards,

John

r61restoration.com

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