On the Hunt for a Crankshaft

[kmisterk]

Last summer y’all helped me stumble through rebuilding the top-end after I stupidly spun a bearing.

It worked, sort of, in that I got the bike back together and running, but the damage was done and the knock persisted.

I have a question. Two, actually.

1. Does this crank look okay? There’s a … gash(?) in what looks like a front bearing surface and I don’t know if it’s kosher or not. https://www.ebay.com/itm?itemId=2253666 ... Watch=true

2. Would I be better off at this point looking for a short block and just transfer over the heads/cylinders etc?

Thanks all! Hoping to get Sheila back on the road before 2024 riding season.

[Rob Frankham]

I wouldn't be happy with that crank. Both mains seem fairly well scored and the various bits of damage to the web and other parts of the casting don't bode well. Not particularly impressed by the fact that the whole thing seems to be covered in metal filings either. That being said, I am not sure what you are referring to by a 'gash' on the front bearing surface. If you are referring to the machined flat in the front main journal...

Crank1.jpg (42.71 KiB) Viewed 1271 times

That is normal. It is there to meter oil flow to the rockers.

If, on the other hand, you are referring to the apparent damage to the shaft...

Crank2.jpg (49.57 KiB) Viewed 1271 times

This isn't brilliant but it won't materially affect the function of the crank because it is located where the sprocket sits.

IOncodentally, the link in your post doean't appear to work. This one should... https://www.ebay.com/sch/i.html?_from=R ... 2&_sacat=0

Rob

[SteveD]

Screenshot 2023-03-10 at 20-46-52 s-l1600.jpg (JPEG Image 1200 × 1600 pixels).png (1.28 MiB) Viewed 1243 times

Have you gained any info, fwiw? ebay answers are dubious I guess and possibly a waste of time.

The only real confidence might come from a pro measuring it. Price, postage and assessment on something that might be assessed as rubbish is a risk. Plan B might be best?

[Rob Frankham]

Have you gained any info, fwiw? ebay answers are dubious I guess and possibly a waste of time.

The only real confidence might come from a pro measuring it. Price, postage and assessment on something that might be assessed as rubbish is a risk. Plan B might be best?

Ouch, hadn't noticed that one. Wouldn't touch that crank with the proverbial bargepole.

Rob

[jackonz]

Screenshot 2023-03-10 at 20-46-52 s-l1600.jpg (JPEG Image 1200 × 1600 pixels).png

Have you gained any info, fwiw? ebay answers are dubious I guess and possibly a waste of time.

The only real confidence might come from a pro measuring it. Price, postage and assessment on something that might be assessed as rubbish is a risk. Plan B might be best?

Hell don't go near that crank, you could try contacting Munich Motorcycles in Australia, link to their website below, they specialise in Boxer BMW.

https://www.munichmotorcycles.com.au/