Starting R50 "Barn Find Condition" Restoration Project

[skogas]

Hello,

I am starting a restoration project of an old and rusty 1955 R50 that I bought at the estate auction here in Australia.

Funny enough - it came with the Californian number plates that had stickers from 1974. The bike was previously in a crash with the damage that hasn't been repaired (badly smashed headlight, bent handlebars, broken throttle cables and whatnot...), so I'm assuming it never ran since then.

Long story short - it is a really challenging project for me, but I'd really love to put it back on the road if I can, and will be needing advise on various topics as it's my first bike and restoration of this kind.

The first question that concerns me the most is the frame geometry, and more specifically - how can I check whether it requires straightening.
There's a fair bit of damage, including badly bent handlebar, somewhat misaligned fenders and rear fender mount, bent muffler etc, but it's really hard to tell if the frame is ok or not.
Unfortunately it's really hard to find this kind of specialist here in Melbourne these days, so it'd be great to get some advise on frame checking.

And another question is - whether I should try to start the engine (as I'm extremely curious to try to run it).
There's no battery at the moment and no ignition key I could use (the headlight is smashed and there's just a spiderweb of cables in it) - but when I try the kickstart - there's a spark in both plugs.
Does it mean that the ignition switch is currently in the "on" state, or is it simply Magneto doing its job?
Can I (and should I attempt to) start it at all before getting the battery, checking valves etc and fixing the electrics?

Please see the condition of the bike and "headlight contents" attached

Thank you

[schrader7032]

Andy -

Welcome! You have quite the road ahead of your...good luck!

As for the frame, I would try the following:

- the wheel base is 1415mm. Put the wheels on, hold the bike upright, and drop plumb bobs to the ground at each axle. Measure the length.
- ensure that the steering is pointed straight...get behind the bike and sight down the rear tire to the front. I believe the wheels should track together, or at least point the same direction.
- bolt something straight to the handlebar mounts, turn the steering as straight as you can and see what that bar looks like.

As for the ignition, something must be messed up inside the headlight shell to make the contact a key would. Inserting a key allows the magneto to work (grounds it or ungrounds it...I just cannot remember which) so you would need to get that fixed. If you try to start it, you might not have a way to stop it...at least easily that I can think of. I'd get farther along with the restoration before considering something like that.

[R68]

Of course we all wish you good luck with your new project, but that motorcycle may be too far gone to restore economically, and after you do your research, may find it better to sell/trade it to someone in your area for a restored or easier-to-restore BMW? Although the headlight is toast, the ignition switch looks to be intact, and so you could likely start the bike (after verifying there's oil in the motor!!!). At the risk of seeming to be a vulture eyeing the carcass, I'd love to get the drivers seat frame (very early 1955) from that bike, and the air cleaner is a rare item specific to a 1952 production BMW. Whatever you do, RESEARCH before taking it apart or spending lot of money!

[skogas]

Hi guys,

Thank you very much for your responses, this helps a lot!

Will get checking the frame today based on you advise and will see how I go!

Testing the front might be a bit tricky, as the handlebar mount (at least the right one) seems to be affected by the crash, so it's really hard to tell what the "straight" is in terms of fork/wheel etc.
I.e. if I'm aligning the wheel so that it appears straight - it hard to be 100% sure that the top fork mounts are straight too, but I guess I might try to do some measurements there to compare the left and right side clearances.
(the bike is missing central stand, and I'm currently using my apartment building's garage, which doesn't help either, hehe)

Also thank you for the your advise re. ignition - so it sounds like it's in an "On" state and I at least need to figure out how to disengage it quickly before trying to start the bike.

@R68 - yes it's definitely a big challenge for me, but at least I gotta give it a shot. The bike has triple matching numbers, so it's "original" in that sense and it'd be a shame to make it a "donor" bike.
What's interesting is that the ID plate says "Baujahr 1953" and "Baureihe" is 1955 - so the early air cleaner is probably original too

Thanks again!

[Darryl.Richman]

You can test to see if the basic frame is straight by measuring the distance from a point on the mid line of the steering head to each of the swingarm pivots. You should get the same number from each measurement.

[R68]

...well that's amazing because I would not have thought the factory would be building Baureihe 1955 as early as Baujahr 1953, but maybe you have some sort of prototype, which would be much more historically interesting/valuable? Your front end is almost certainly post 1957, as is your exhaust system. There are however some details on the bike that are very early (seat frame, breather cover retainer)... you need to do your research? Search the internet for Duane Aushermann's websiten that addresses the specific characteristics of the very early swing arm twins...are you amenable to telling us your serial number???

[R68]

...what Bing carb's do you have? Is there a 6mm hole in the rear fender centrally placed immediately above the license plate bracket? What are the numbers stamped in the undersurface of the lower fork brace?...is there evidence of two holes for the license plate bracket instead of three?...fascinating motorcycle!...

[R68]

...are there numbers stamped in the top of the timing chest cover and the motor case and the generator/magneto cover, and do they match?...

[R68]

..there a several BMW enthusiasts in your country who you should contact for information about your possibly unique BMW; they might be interested in buying it from you?..please don't just part this bike out on "e Bay"!...

[jimkav]

R68,
How do you find out number in production run?
I have a 55 R50 - came out of deceased previous owners estate sale.
Matching numbers 551592
Just pulled engine for rebuild.
Never seemed to have been apart.
Original paint/controls/dimpled headlight bucket ect
Thanks