Vintage BMW Motorcycle Owners

Hi,

Kind of a longshot, but I'm looking at a basket case R51/2 for sale but it is lacking several pieces, the most worrisome is the crankshaft (and perhaps the camshaft, not sure yet). I'm wondering if perchance someone might have one on a shelf somewhere? It doesn't need to be in great shape, I'm not picky would send it along somewhere for a rebuild.

Regards

Rob

I am restoring an R 51/2 right now. The camshafts (2) are available (I just bought them).

The crankshafts I am not too sure of. After looking at mine I feel an R 50 crank might fit at first but I would need to ask others about that. I will measure both cranks tomorrow and let you know.

If you can share pictures of the motor and the chassis number and and I can tell you more about it.

Wow, what are the odds!

It wouldn't be surprising if the R50 cranks would fit as from what I gather, the big changes in the engine came in 1951 for the /3 models. Unfortunately I don't have any good pictures as it's still not mine, only this one, but the serial number on the engine case appears to be 518662
I would suspect a crank from a R50 would be "easier" to find...

Thanks again,
- Rob

Hello Rob,

Not such a longshot after all. We just completed a two year build of a 1950 R51/2 sport bike while working on a restoration and service manual for the R51/2 and have an extra crankshaft as well as a quite a few other R51/2 parts including a rebuilt transmission, rebuilt generator and complete distributor remaining in storage that are available. I'll take a critical look at the crankshaft this morning and if you will confirm you are still in need of a crankshaft I'll get back to you with a report on the condition of my extra.

Christopher Betjemann
Barrington Motor Works Publications
Barrington, NH

Oh wow! wasn't expecting that!

I'll reach out to the seller to confirm that it is still available and if so, I would certainly take the crankshaft! Even if it has issues, I could send it for a rebuild...

Thanks Christopher, one step closer to getting a R51/2 back on the road!

Rob