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1937 BMW R5 Restoration

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caker
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1937 BMW R5 Restoration

Post by caker »

Very happy to report completion of my 1937 BMW R5 restoration. It is complete and running, but too cold and gross weather here to take it out to do the final tuning and break-in. That will have to wait until Spring.

I bought this project maybe 7 or 8 years ago - a non-running (barely rolling) basket case. It was missing a few parts and was far from able to run, so I never messed with it -- it just sat waiting for its turn. Its history before me: it came out of southern California, and before that it was in Ohio. My impression is it was with that owner in Ohio for quite a long time. Amazingly, the bike was really well preserved. Lots of original fasteners and all the "weird" R5-specific stuff was more or less there!

Here's what the archive says:

> The R 5 engine-no. 501140 and frame-no. 502484 are matching. Your BMW R 5 was produced on 02.12.1937 [December 2, 1937] and delivered on the same day to the dealer Falcon Works in Isleworth/Middlesex, Great Britain.

A rare export bike! With a "miles" speedometer. I've reached out to the AFN / Falcon Works / Frazer Nash archive but have not been able to get any response.

Here's what I started with as I brought it over to my home shop. This was Aug 2023:

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After some disassembly, I removed the motor and put it onto my engine stand. It did not take long to discover a major problem:

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This was more a blessing than a curse - as apparently this was a common problem on R5s, and in my particular case it was a VERY clean break. The pieces fit back together almost seamlessly, so I wasn't that worried about a repair.

The blessing is because I believe this catastrophic fault is what put the bike up for so long in mostly untouched condition. Almost every fastener and all the sheetmetal was original, original speedometer, generator, horn, and so on...

-Chris
Last edited by caker on Sun Jan 19, 2025 7:26 pm, edited 2 times in total.

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Re: 1937 BMW R5 Restoration

Post by caker »

Here are a few pics of how we addressed the broken head:
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Here is some welding advice my friend Kevin Koch in Germany gave me.

So between that advice, the "precision" jig I made, plus the perfectly fitting break, plus a really good welder and we got it back in one piece!

But what caused the failure originally? This was obvious: both the exhaust and intake valve stems were mushroomed out at the very top. The exhaust was way worse and this was the side that broke. So, I'm guessing the valve guide clearances were too tight and it started to hang valve(s) and, well, something's gotta break.

It is interesting to see the design changes that were made to heads from this generation onward. Definitely lessons learned by BMW...

-Chris

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Re: 1937 BMW R5 Restoration

Post by caker »

"Miles" speedometer. You can see the hand-painted "Miles" under the Veigel logo. I've since cleaned up the speedometer, and also are hand painted serial number and a ratio, but they're barely visible.
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-Chris

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Re: 1937 BMW R5 Restoration

Post by caker »

Beautiful castings after cleaning, dry sand blasting, and then wet bead blasting:
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Here is one of the "weird" R5/R6 specific hardware pieces. This is for the rear flip-up fender stay to the frame. It has a nut captured by a washer you'd stick on the end and then swage out the little nub to retain the washer. I had both sides!
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-Chris

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Re: 1937 BMW R5 Restoration

Post by caker »

Some assembly...
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Re: 1937 BMW R5 Restoration

Post by caker »

I did the body and paintwork myself. I painted each part - likely more than once. I am a newbie painter. Most parts got two part DTA epoxy primer, then DTM building primer before single stage gloss black. I used and liked Tamco's products.
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Last edited by caker on Sun Jan 19, 2025 7:23 pm, edited 2 times in total.

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Re: 1937 BMW R5 Restoration

Post by caker »

I sanded and repainted the tank at least 3 times. A major breakthrough was better lighting in my booth. You need direct reflections to see stuff, otherwise you're "paint in the dark" !
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Todd Hanson out of Ohio did a great job on the pinstripes

-Chris

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Re: 1937 BMW R5 Restoration

Post by caker »

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It has higher compression R50S pistons and rods and a Chris Chambers crank that's been in a box for years. Reunited and the bike sounds good! Hoping for a nice day soon.

This turned into a photo dump, as I have about 500 pics so it's hard to choose, but it was fun to go back through all of them. Thanks to Jeff Moore for his help getting the plating and welding repair done. I also used PowerSeal USA for cylinder boring (they were awesome), and advice from Randy Long and many others - it takes a village. I hope I can help the next person.

-Chris

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Re: 1937 BMW R5 Restoration

Post by sherman980 »

Chris,
A job VERY well done! Congrats on a great outcome!
Chuck S.
Thanks.
Chuck S

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Re: 1937 BMW R5 Restoration

Post by cwf »

Looks great, well done. The BMW club UK has records of BMW bikes sold by AFN 1935-1939. This is who you want : Ken Buchanan, dvla2@bmwclubuk.net

Charlie.
75/7+ offroad sidecar; 50/2; R 35; XR125V; XR200A; Solex; 1939 Hillman Minx DHC.

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