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Frenia
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Hello,
I have a 1956 R50. I’m rebuilding the engine. One of the crank’s wrist pin bushings is loose/fell out. What is the preferred way to repair this issue? Bob’s BMW says they can knurl the bushing and press it back in. What about the cycle works tool? I don’t see them selling it anymore. Any help is greatly appreciated.
Thanks Doug Frenia

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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Crank's wrist pin bushing?

Crank's wrist pin bushing? Not sure what that is. Is it on this figure:

https://www.realoem.com/bmw/enUS/showparts?id=0211-EUR-02-1956-T50-BMW-R...

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Frenia
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Hi, It's # 22 on the

Hi,

It's # 22 on the diagram.

Thanks

Captonzap
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Wrist pin bush

What you are looking for is the number 22 on the illustration.

CZ

Edit;

OOp's, looks like I type slow.

Twocams
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Why not take it to a machine

Why not take it to a machine shop. They can mic the wrist pin and rod hole to make another bushing. Maybe use some oilite bronze bushing.
twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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Rist pin bushing

The bushing is available and needs the special tool to insert it and fit it inside the rod for a proper fit

Since you already have the engine out I would just bring it to Bob's and have both bushings replaced
!/2 hour labor or minimum charge

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

Twocams
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Why does it take have to have

Why does it take have to have a special tool to insert?

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

Captonzap
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because

Some people don't have a piece of all-thread , a selection of washers, and a couple of nuts.

wa1nca
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VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
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rist pin Bushing

Once the new bushing is installed it needs to sized to the connecting rod

This is a copy from my Barrington book
Another reason why anyone doing this kind of work should have this manual

Tommy

  • dsc04337.jpg
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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
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If I'm not mistaken, the

If I'm not mistaken, the centering of the bushing should be done in concert with the other bushing. By rotating the conrods around to one side, it's possible to ensure that the two centers of the bushings are inline with each other.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

johnpst
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Hawaii
Joined: 03/22/2016
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REPAIR IT PROPERLY

Aloha,

Your bushing came out because it's been pounded the point where it's actually shrunk from it's significantly tight designed fit. Do not use glue, knurling, or other voodoo magic to repair what is a ~$5.00 part and, as said above, 30 minutes work for an experienced shop.

Dan's tool works extraordinarily well, i highly recommend it but, if you are rebuilding the engine, you must suspect the crank shaft is due for inspection. It's also possible, and likely, the con-rod bearings may require some attention. For a few hundred bucks, the crank can be disassembled, con-rod bearings inspected/repaired, new bushings installed and sized to your gudgeon pins, pistons and con-rods moment balanced, flywheel tapers cleaned and honed to your flywheel and dynamo rotor, etc. It's not much to pay for reliability.

If that's not your plan, the Dan's tool works very well. I've made multiple repairs on various bikes with mine without issue. Takes me 20 minutes to get the cylinder and piston off, sometimes up to an hour to get the new bushing in and properly sized, and we're on the road with a properly repaired bushing, sized correctly for the application.

John

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John
55 - R50, 06-R1200RT, 96-M900, 10-TU250x

Frenia
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Thanks

Hello,

The Crank is already at Bob's BMW. I have a new bushing on the way and will have them insert and size.

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