Page 1 of 2 1 2 LastLast
Results 1 to 15 of 16

Thread: New acquisition

  1. #1

    New acquisition

    I just picked up what is essentially a "barn find", but was stored well. I had the pictures long enough to notice some conflicting details. Motor and Frame tag number match (and show to be to an R50/2), but it has two fin valve covers like an R50S, R69 or R69S, and also has the "bumped" front cover like an R69. PO says it was sold to him as an "RS50", but was told it had "600 heads". It DOES look like an R50S, but I think what I have is an R50/2 with R69 0r R69S heads and valve covers. Further dis-assembly is coming so I will be able to get a P/N off the crank. Far as I can tell, it is only missing mufflers and the handlebars. So I have my winter project. Not even going to consider any other course of action than taking the motor down for slinger clean/inspect. It will eventually get a frame-up resto.
    Attached Images Attached Images

  2. #2

    A few more detail pics...

    A few more detail pics for ID confirmation
    Attached Images Attached Images

  3. #3
    neanderssance man sedanman's Avatar
    Join Date
    Jul 2011
    Location
    Pawling NY
    Posts
    792
    NICE! If it were mine (here we go with opinions) I would make sure it was mechanically sound and ride it. You can restore them a hundred times but they're only original ONCE.
    Paul
    Stop wrestling with your motorcycle, dance with it.
    2011 R1200RT Traded
    2014 R1200RT fully optioned

  4. #4

    Temtation....

    I am seriously tempted. The carbs are clean, it has spark and respectable compression. I suspect I could have it running in a weekend, but I have seen so many strong opinions about the danger of doing so with possibly clogged slingers that I would feel like I was doing a "Slim Pickens" in Dr. Strangelove. So I am gonna wuss out, and do the motor first. It would be a huge shame to lunch that crank after all these years....

  5. #5

    It does not look to be a match

    I think the VIN would start off with a 564... and the final drive would be stamped 25/7 to be an R 50S. Nice little project, could probably be as you said an R 50 with R 69 heads, front cover and carbs. R 50 carbs would be 1/24/45, 46. R 50S would be 1/26/71, 72 and R 60 would be 1/24/125, 126.

    You can also look on the underside of the earles front end lower tree and see if its got the stud for the hydraulic steering damper.

  6. #6

    Speedo too

    Speedometer for R 50S wouldn't have a trip reset knob.

  7. #7
    neanderssance man sedanman's Avatar
    Join Date
    Jul 2011
    Location
    Pawling NY
    Posts
    792
    Quote Originally Posted by jimbob1960 View Post
    I am seriously tempted. The carbs are clean, it has spark and respectable compression. I suspect I could have it running in a weekend, but I have seen so many strong opinions about the danger of doing so with possibly clogged slingers that I would feel like I was doing a "Slim Pickens" in Dr. Strangelove. So I am gonna wuss out, and do the motor first. It would be a huge shame to lunch that crank after all these years....
    Alll well and good, falling under the guise of "making sure it's mechanically sound". Doesn't mean you have to blast and paint the engine parts when you reassemble.
    Paul
    Stop wrestling with your motorcycle, dance with it.
    2011 R1200RT Traded
    2014 R1200RT fully optioned

  8. #8
    Liaison 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    22,659
    The VIN shows it as an R50/2 built in the first couple of weeks of March 1967. Check the listing of VINs and models in the thread at the top of this forum.

    It's a little hard to tell, but the valve covers appear to be R50S covers. Duane Ausherman shows an R69 cover on the left and an R50S cover on the right in this picture:

    http://w6rec.com/duane/bmw/slash_2/d...alvecover3.jpg

    It appears that the two horizontal fins go all the way round to the fins that circle the cover. This is a characteristic of the R50S covers. They're pretty hard to find. I don't recall if the R50S covers will fit the bigger engine.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  9. #9

    ...further ID...

    OK, weirder and weirder. Carbs are 1/24/131 and 1/24/132. Here is a more detailed shot of the VC. Bike has the sidecar ball and lug. I am 90% sure it isn't an "S" of any displacement from the factory, most things point to a later production plain vanilla R50/2. PO acquired the bike in 1974, stopped riding it winter 1976. My guess is that the same stuff got torn up in a crash back then as would now, and this was a bike repaired on the cheap with salvaged parts from another bike. Or, a savvy /2 owner begged, borrowed or stole a set of high compression heads off of a wrecked R50S. The jugs are round, which I am pretty sure means 500. Any idea if a R50S top end would just drop on to a standard R50/2 case? I would have thought they might do.

    "This is indeed a mystery..." ,remarked Watson. "What do you imagine that it means? Holmes replied "I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suite theories, instead of theories to suit facts."

    This is too much fun already. However it is a glorious Sunday morning in Calgary, and we don't have many left before the weather goes off. I KNOW the red bike in the parking lot is a 1980 R100RT, and I am going to start up that "known quantity" and head for Drumheller. More Sherlock Holmes stuff later.

    Thanks for the comments and clues folks!! Really appreciate it!!

    JimBob

    1980 R100RT
    1967-68 R50? (whatever the heck it is, it's cool and has Earles forks...)
    1978 SR500
    1971 Rokon RT-140
    (and my wife's Honda Airblade in Saigon)
    Attached Images Attached Images

  10. #10

    I'm sure the 50S top end is a bolt on

    I'm pretty sure the R 50S heads and stuff will bolt right on, that was an issue with the 50S as they had standard built bottom ends and they wiped out crank shafts because of the higher top end. The valve covers are unique and also the air tubes, I have never compared 50 /2 air tubes with an R 50S but mine certainly are different from my R 60US and my '55 R 50. Anyway sounds and looks like somebody has a nice little hot rod to play with.

  11. #11

    Question Hmmmm...

    I was wondering if, assuming someone has grafted R50S top ends on this little gem, the bottom end would take the stress of the higher compression. Guess I will need to look at what the differences are between a standard R50/2 crank, rod, big end bearing and piston. Would seem to make sense to build for it, since I am going to clean/replace the slingers, and had planned to do all the bearings while I was in there. I am waiting on the Barrington rebuild bible, anyone know if it will have all the dimensional info for the various varieties of innards? Curious what the differences would be since they have the same bore and stroke. Beefier crank journals and pins? Beefier pistons and pins on top? Higher flow oil pump? Any differences in the crank case? Same number of mains, etc? Could it be as simple as ordering R50S components?
    Hmmmm...NOW I gotta do some serious research....



    1980 R100RT
    1967-68 R50/U (unknown...)
    1978 SR500
    1971 Rokon RT-140
    (and my wife's Honda Airblade in Saigon)

  12. #12

    Unhappy Next chapter in the rebuild

    Wow, am I ever glad I didn't just get this bike running. I sent the motor off to Mr. Brooks for a rebuild....when he got it apart, he discovered why all the "frankenparts" were there. At some time in the dim past, the poor thing grenade'd a piston. The jasper who worked on it apparently dropped on a new jug, head and piston (first over...leaving the stock set up on the other side...). All the debris was left in the case.....looks like the crank is salvageable, but if I had fired it up, it would have likely been a very short run. Given what a replacement crank would cost, I am really glad I listened to the doomspeakers!!!
    Attached Images Attached Images

  13. #13

    The slingers

    There is a lot of bad juju in that slinger....
    Attached Images Attached Images

  14. #14
    Liaison 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    22,659
    There's enough in that slinger to build another motorcycle! Wow!!
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  15. #15
    Rally Rat 1074's Avatar
    Join Date
    Sep 2004
    Location
    Las Vegas, NV
    Posts
    1,154

    Valve covers

    Just off the top of my head, I'd guess that those valve covers are from a /5 or /6.
    Boxerbruce

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •