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Thread: '63 R50, broken left side exhaust valve spring

  1. #1
    Registered User robday's Avatar
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    '63 R50, broken left side exhaust valve spring

    Well, I finally found a vintage Beemer. It was fully restored, but has been registered "non-op" since 1993.
    It was running beautifully on my inaugural ride up the coast. Had lunch, got back on and about 4 miles later the left cylinder lost compression and started making a racket (ugh).
    I stopped and called AAA to bring me home. This morning I popped the valve cover off, and saw the exhaust spring in 5 or 6 pieces.
    Next step is to pull the head and see if the piston or cylinder is damaged.
    Anyone had something like this happen to them? I could use some advice, this is my first airhead.
    At this point I'm inclined to pull both heads and have new valves/springs installed. If these are the original springs, they might just be too old.
    Previous owner had the engine rebuilt with new pistons, rings, valves, etc. but I'm not sure if he replaced the springs.
    The exhaust valve feels a little sloppy in the guide, also not sure if this is normal or not. Also not sure if the valve was contacting the piston, but will know once I pop the head.

    Feel free to chime in if you have advice or ideas! I'm fixing it regardless of what it costs...
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    '92 K75S, all black...
    '08 K1200GT, silver...
    '06 R1200GS, silver...
    '63 R50/2, black...

  2. #2
    Administrator 20774's Avatar
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    I saw your post on the Vintage BMW forum. I think you should got the bad luck with some bad springs. I just had my /7 top end redone and the rebuilder measured my springs and they were sacked, so he installed new ones. Maybe yours were indeed over the hill.

    Good idea to pull everything and take a look. The best source for help and parts is Vech at Benchmark Works. I'll have to say that when I sent him my head from the R25/2, he farmed that work out to Memphis Motorwerks. So, it might be reasonable to consider going straight to the source unless you wanted Vech to do other work for you. I think Bob's BMW also works on vintage bikes...most likely Max BMW, too.
    Kurt -- Forum Administrator ---> 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!

  3. #3
    Registered User vechbmw's Avatar
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    Broken valve springs plus some observations

    Having worked on Earles fork twins for many years, I can tell you that what happened is pretty rare. However, new valve springs, both inner and outer are still available new.
    The part numbers are:
    11 34 0 026 110 valve spring inner R24-R60/2 original
    11 34 0 026 118 valve spring outer R24-R60/2 original
    I'd replace all of them..........
    Also, I noticed that the valves are the non rotating type. You would be better off to pull both heads, and replace the valves with the later rotating type, they resist burning much better.
    However, if you do this, be advised that you must also buy new valve keepers and upper spring seats.
    These parts are all available also:
    11 34 0 026 170 valve intake 2-groove rotating type R24-R60/2
    11 34 1 251 472 valve exhaust 2 groove rotating type R24-R60/2
    11 34 0 026 460 valve stem keeper for rotating valves two grooves
    11 34 0 026 180 spring cap upper for rotating valves R24-R60/2

    Do yourself a favor after you get the heads off, and take all of your push rods, lay them on a glass coffee table and roll them. If you see any hop at all, in any push rod, REPLACE it, it is bent and no longer usable..
    These parts are all available also:
    11 32 0 033 170 pushrod R51/3-R50S

    Feel free to call me if you have any technical questions, during business hours 662 465 6444

    Vech
    MOA Ambassador #9462
    Bench Mark Works

  4. #4
    Registered User robday's Avatar
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    Quote Originally Posted by vechbmw View Post
    Having worked on Earles fork twins for many years, I can tell you that what happened is pretty rare. However, new valve springs, both inner and outer are still available new.
    The part numbers are:
    11 34 0 026 110 valve spring inner R24-R60/2 original
    11 34 0 026 118 valve spring outer R24-R60/2 original
    I'd replace all of them..........
    Also, I noticed that the valves are the non rotating type. You would be better off to pull both heads, and replace the valves with the later rotating type, they resist burning much better.
    However, if you do this, be advised that you must also buy new valve keepers and upper spring seats.
    These parts are all available also:
    11 34 0 026 170 valve intake 2-groove rotating type R24-R60/2
    11 34 1 251 472 valve exhaust 2 groove rotating type R24-R60/2
    11 34 0 026 460 valve stem keeper for rotating valves two grooves
    11 34 0 026 180 spring cap upper for rotating valves R24-R60/2

    Do yourself a favor after you get the heads off, and take all of your push rods, lay them on a glass coffee table and roll them. If you see any hop at all, in any push rod, REPLACE it, it is bent and no longer usable..
    These parts are all available also:
    11 32 0 033 170 pushrod R51/3-R50S

    Feel free to call me if you have any technical questions, during business hours 662 465 6444

    Vech
    MOA Ambassador #9462
    Bench Mark Works
    Thanks, Vech!
    I've been talking to Rick at Black Kat Restorations here in Los Angeles, and he basically said the same thing. The plan is to pull the heads and have them completely redone.
    And since the internal history is a mystery, I'm also going to pull the case and check it out, possibly replacing the slingers if necessary. I have a stack of receipts from the previous owner that show he bought new pistons and rings, but no mention of opening the case or replacing the valves or springs. I did notice that the clean oil was already looking dirty after 48 miles, and the unknown condition of the slingers will eat at my brain unless I open her up and have a look.

    I think that one valve guide might have come loose, the valve is loose in the head and wobbles freely. I'm concerned that it might have ruined a piston, and sent debris through the crankcase. I'll know more once I pull the heads.
    I recently purchased Barrington Motor Works restoration manual (where you are prominently mentioned!), so I have the procedures. Rick had mentioned a few tricks for getting the case out without scratching the frame, too.

    I appreciate the advice. And I will definitely be calling you at some point. It's good to know that a) Rick's advice is sound, and b) there's someone to call for an expert opinion. I'll take pics along the way and post them here as well.
    Rick has a machine shop he likes a lot. They have a 3-4 week backlog, but that's fine with me if they do good work. With my weird schedule (and the fact that I usually spend my days off riding instead of wrenching), it will probably take me that long to get the case out anyway.

    The bike was running pretty darned good for those 48 miles. I was babying it because I'm pretty sure I'm the first rider since restoration. Hopefully by shutting her down as soon as the racket started I was able to minimize the damage. We'll see, likely on Tuesday or Wednesday. Unless I'm riding....
    '92 K75S, all black...
    '08 K1200GT, silver...
    '06 R1200GS, silver...
    '63 R50/2, black...

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