BMW K bikes (Bricks)


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TRIceberg

TRIceberg
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I've been leaking small amounts of oil from my cylinder head cover for awhile now, and yesterday I finally removed the cover and found this:

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449884399_60df24e775

Not sure how this happened, and as of now, I have yet to locate the piece of metal that broke off!! The retaining bolt can't get any grip and this site is the source of the leak.

any help would be much appreciated.



Last edited by TRIceberg on Sun Feb 10, 2013 1:13 am; edited 1 time in total


__________________________________________________
1985 K100rs
1972 R75

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449926619_191bc78201_m
    

charlie99

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i cant get the link to work

try here for posting pics ..

https://www.k100-forum.com/t998-posting-pictures-and-movies


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

TRIceberg

TRIceberg
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Here's another link if the above photo isn't working
http://www.flickr.com/photos/70983501@N06/8449884399/


__________________________________________________
1985 K100rs
1972 R75

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449926619_191bc78201_m
    

88

88
Life time member
Life time member
I would take off the whole engine bottom plate and not just the Oil filter cover to see if the missing metal is in there, with the size and weigh (assuming it came off in one lump and it looks like it did) it should have worked its way down there.

88


__________________________________________________
[solved]Broken Camshaft Bearing Cap... Suggestions? Ir-log1188....May contain nuts![solved]Broken Camshaft Bearing Cap... Suggestions? Ir-log11

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

K1 - 1989 - AKA Titan (unique K1/K1100RS hybrid by Andreas Esterhammer)
K1100RS - 1995. AKA Rudolf Von Schmurf (in a million bits)
K100RS - 1991 AKA Ronnie. Cafe racer project bike
K75RTP - 1994
K75C - 1991 AKA Jim Beam. In boxes. 
K1100LT 1992 - AKA Big Red (gone)
K100LT - 1988 - AKA the Bullion brick. Should never have sold it.
    

nino

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Ask experienced machinist. Broken thread isnt much stressed, its just for cylinder head cover, but oil and high temps ask for profesional advice and service

    

charlie99

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could the piece of metal been retreived by the "po" already ?

possibly you could have the saddle rewelded and tapped to take a bolt again ? as finding a suitiable candidate could be troublesome .

job for a pro i recon .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

TRIceberg

TRIceberg
active member
active member
Thanks for the replies. I'll dig into the engine to hopefully find the missing metal. As for new threads... I know the caps are matched to each section of the case they attach to, but I've also seen posts about people getting replacements from "junked" engines. Any thoughts on this?

Also what about sealing off the hole on the case cover to prevent oil leakage? The only leak is through that hole, so the other bolts must be sufficient to prevent leakage around the rest of the cover. Could an epoxy with a high heat tolerance work?


__________________________________________________
1985 K100rs
1972 R75

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449926619_191bc78201_m
    

nino

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You have to find heat and oil resistant epoxy. It could work but carrefully with tightening.

    

Themason

Themason
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The caps are line bored with the head during manufacturing so they become a matched set. Since there is no bearing insert a cap from another head probably would not work. Used heads are cheap. That is how I would proceed. Welding the cap risks distorting it and causing more problems.


__________________________________________________
I live in a parallel universe but have a vacation home in reality :arrow:

1984 K-100RS Alaska Blue w/Parelever and 16V wheels.

1984 K-100RS Metallic Madison stock

1986 R-80G/S w/1000 cc engine

2007 Harley Davidson Street Rod Mirage Orange w/XR1200 wheels, Race Tech, True Track, Works Performance shocks

2007 Harley Davidson Street Rod Vivid Black stock

1993-ish K-100/1100RT/LT hemaphrodite frankenbike thingy to be painted satin black from a rattle can eventually
    

Rick G

Rick G
admin
admin
What Nino has suggested is about the only way you will have a chance of a repair without removing the head. I would try the Permatex strip epoxy and rough the cap with a burr before you start and clean it with the carb and injector cleaner. I will say it would hold provided you are gentle with the spanner when tightening the bolt.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

japuentes

japuentes
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Themason wrote:The caps are line bored with the head during manufacturing so they become a matched set. Since there is no bearing insert a cap from another head probably would not work. Used heads are cheap. That is how I would proceed. Welding the cap risks distorting it and causing more problems.

I agree, best bet is a used head.

Best regards
JAP


__________________________________________________
[solved]Broken Camshaft Bearing Cap... Suggestions? 2854237993 1988 K100RS SE/ABS
    

TRIceberg

TRIceberg
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Thanks guys. I'll start with the epoxy fix and see how it holds up. Hopefully it won't come down to changing out the head. I'll check back in soon with an update.


__________________________________________________
1985 K100rs
1972 R75

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449926619_191bc78201_m
    

sidecar paul

sidecar paul
Life time member
Life time member
Hi TRIceberg,
I've just taken a bearing cap off my spare engine to see if I could suggest a solution.
The 6mm thread in the cap is about 17mm deep, the thread on the cover bolt is about 13mm long and, from your picture it looks as though the cap is broken at about the 13mm deep mark. Now, if you were to fit a 6mm stud, say about 40mm long into the bearing cap, there might be just enough thread to hold it in place. I'd use either epoxy or Loctite to fix it and then use a nut and washer with the standard rubber seal (and maybe a bit of silicon sealant) to hold the cam cover. A dome nut would make it look pretty.
Could be easier than replacing the head.
Good luck,
Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

yankeeone

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There was a forum member who had the same problem a few years ago, they put a used one on, I wonder how they made out in the long run. I would try that, particularly if I wasn't going around the world on the thing.

    

japuentes

japuentes
Life time member
Life time member
Hi there, following Paul´s idea I guess you could make a saddle with a nut welded to it and hold in place by the cap bolts, as show on the draw

[solved]Broken Camshaft Bearing Cap... Suggestions? Cap_sa12


Being steel the nut can hold the stress, keep the original cap centre hole so the original bolt can be used.
Make the saddle legs as long as possible to assure maximum stiffness.
Hope this helps.
Best regards
JAP


__________________________________________________
[solved]Broken Camshaft Bearing Cap... Suggestions? 2854237993 1988 K100RS SE/ABS
    

charlie99

charlie99
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great suggestions paul and jap


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

sidecar paul

sidecar paul
Life time member
Life time member
JAP,
I like that idea.
I suppose it depends on what machining facilities are available, but based on your thoughts, if the top of the cap were to be milled flush, a simple plate between the cap fixing studs with a 6mm tapped hole should work. Just need to get the heights right.
Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

japuentes

japuentes
Life time member
Life time member
Yes Paul thats the idea, grind the cap, flush with the nut base, and the saddle is a bent plate, thickness like a washer or so. The u shape is what gives the required flexural stifness.
Best regards
JAP


__________________________________________________
[solved]Broken Camshaft Bearing Cap... Suggestions? 2854237993 1988 K100RS SE/ABS
    

sidecar paul

sidecar paul
Life time member
Life time member
Hi guys,
As you know I like a challenge, especially if it means making swarf. bounce
Although my original idea of a 6mm stud would probably work, JAP's idea was more elegant and retains the original elaborate cover bolt, so I had a play this morning.
Firstly I made a note of the significant dimensions.

[solved]Broken Camshaft Bearing Cap... Suggestions? Sam_0510

I then milled a block of alloy to replicate the height of the cover fixing hole, tapped M6.
[solved]Broken Camshaft Bearing Cap... Suggestions? Sam_0511

Fortunately the camshaft bearing cap fixing studs are long enough to accomodate the thickness of the alloy block without having to cut back the bearing cap. (Hmm, I wonder why BMW made them so long?)

[solved]Broken Camshaft Bearing Cap... Suggestions? Sam_0512
Well, that would seem a good way of going about this repair and it still retains that pretty cover fixing bolt.

So, TRIceberg, doing it this way would only mean filing away the broken section of your cap to allow the alloy block to sit squarely on the original fixing faces: and as I don't have a use for this lump of alloy now, if you want it, PM your address to me and I'll post it on to you.
Cheers,
Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

yankeeone

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Platinum member
Platinum member
Hey, nice job!

    

Themason

Themason
Gold member
Gold member
I am willing to bet swapping heads would take less time than this process.


__________________________________________________
I live in a parallel universe but have a vacation home in reality :arrow:

1984 K-100RS Alaska Blue w/Parelever and 16V wheels.

1984 K-100RS Metallic Madison stock

1986 R-80G/S w/1000 cc engine

2007 Harley Davidson Street Rod Mirage Orange w/XR1200 wheels, Race Tech, True Track, Works Performance shocks

2007 Harley Davidson Street Rod Vivid Black stock

1993-ish K-100/1100RT/LT hemaphrodite frankenbike thingy to be painted satin black from a rattle can eventually
    

japuentes

japuentes
Life time member
Life time member
This one became a multinational project
Great job Paul
Best regards
JAP


__________________________________________________
[solved]Broken Camshaft Bearing Cap... Suggestions? 2854237993 1988 K100RS SE/ABS
    

K75cster

K75cster
Life time member
Life time member
The mason said it may be quicker to replace the head= It might be quicker to order another cap from a wreckers and then machine off the cam tunnell and then clean off the crook cap hat and add the bought one to the existing cap. a similar amount of fun as is being experienced here at present,? maybe?


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

nino

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Excellent job Paul

    

TRIceberg

TRIceberg
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PM sent

Thanks to everyone for the help. I went from no options to several good possibilities in a matter of days! I'm gonna wait for the piece from paul. I've never seen a thread where someone builds a replacement part for another member (for curiosity's sake btw) and then, having no use for the part, offers it free of charge! Simply amazing. I'll post a picture once I get it set up. Thanks again.


__________________________________________________
1985 K100rs
1972 R75

[solved]Broken Camshaft Bearing Cap... Suggestions? 8449926619_191bc78201_m
    

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