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Lesson Learned: You can't judge a book by its cover!

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VintageJim
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Location: Arizona
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Lesson Learned: You can't judge a book by its cover!

Post by VintageJim »

Several months ago I purchased a very nice looking 1956 R26 that had receipts from engine and trans rebuild in the early 1990s from a BMW dealer and also new tires at that time. The owner died shortly after the rebuild and the bike sat for many years but was stored properly. It still has the 1990s tires on it that show very little wear, and original brake shoes.
I purchased the bike without starting it because I wanted to check things out. Well, one thing lead to another until it has now become a mechanical nut and bolt restoration. I just pulled the crank and to my amazement the slinger was full and the awful sight of the snail trail of debris has enter the crank pin. Amazingly enough, the rod bearing still feels smooth. Looking at the bike and the documentation and history I would never have seen that coming.

What is with that slinger design? You can see in the picture that it only allows capture of 3/16" before the debris reaches the crank!! Before disassembly I had assumed it must be at least 1/2"

I sent the head and cylinder to Max in New Hampshire and they are going to do a first over bore with new piston, and I am sending the crank for rebuild and balancing with the new piston. I will let you know what condition the crank is in!
Jim
Attachments
R26.jpg
Slinger 2.jpg
Crank.jpg
Slinger Design.jpg

808Airhead
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Re: Lesson Learned: You can't judge a book by its cover!

Post by 808Airhead »

My motto rings true......"Be ready to rebuild the whole goddam thing!" :lol:
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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VintageJim
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Location: Arizona
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Re: Lesson Learned: You can't judge a book by its cover!

Post by VintageJim »

Thomas, you are absolutely correct! I just got some good news from the machinist at Max who told me the crank showed no wear so he can just polish it and balance with the new piston. Hard to believe after seeing the full slinger and spillage of debris into the crank pin, but I was lucky on this one and glad I never tried to start the engine.
Jim

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