Crankshaft bearing shields: an option?

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Tomcatfixer
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Crankshaft bearing shields: an option?

Post by Tomcatfixer » Fri Apr 10, 2020 4:41 pm

I'm preparing to simultaneously overhaul five Ural engines...

2020-04-10 16.11.29.jpg

...and, as part of the process, I'll be replacing a bunch of old Russian bearings with quality modern bearings...

2020-04-10 16.09.03.jpg

...but, I've got a crankshaft bearing question.

The conventional wisdom is to use an unshielded rear crank bearing so that the oil can flow through the bearing to properly lubricate it, then drain out the hole at the bottom of the bearing carrier plate.

2020-04-10 16.17.32.jpg

The thought was that, despite the advantage of reducing the possibility of a rear main seal oil leak, having a shield on the rear side of the rear crank bearing would inhibit proper bearing lubrication oil flow.

I would love to reap the oil leak reduction benefits of a rear shield, but not at the expense of sufficient bearing lubrication.

I've seen other Uralista try to get the best of both worlds by cutting notches in the shield, like this...

2020-04-10 16.40.18.jpg

What is the opinion of the Collective on such a strategy? Maybe cutting a few additional notches, as well?
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- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Snakeoil
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Re: Crankshaft bearing shields: an option?

Post by Snakeoil » Fri Apr 10, 2020 4:49 pm

:lurker:
Regards,
Rob
Proud member of the Peanut Gallery
2000 Ural Tourist
40 Pilots, 122 Mains
Before you say something stupid, always ask yourself, "What would Harpo say?".

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Re: Crankshaft bearing shields: an option?

Post by Manscout » Fri Apr 10, 2020 5:23 pm

Hmmmm. I am going to show my incompetence, but why a shielded one? If there is a drain hole on the back-side, isn't oil going to get there regardless?
"It goes nowhere fast, and everywhere cool".

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Tomcatfixer
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Re: Crankshaft bearing shields: an option?

Post by Tomcatfixer » Fri Apr 10, 2020 5:43 pm

Manscout wrote:
Fri Apr 10, 2020 5:23 pm
Hmmmm. I am going to show my incompetence, but why a shielded one? If there is a drain hole on the back-side, isn't oil going to get there regardless?
Theoretically, the shield will help keep the oil from seeping past the rubber rear main seal to the clutch bellhousing.
The drain hole returns the oil back to the sump.
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Crankshaft bearing shields: an option?

Post by Tomcatfixer » Fri Apr 10, 2020 7:30 pm

I hauled out all of the "patients", so you get a better visual of the situation. :|

2020-04-10 19.26.43.jpg
2020-04-10 19.26.55.jpg
2020-04-10 19.27.10.jpg
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- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Crankshaft bearing shields: an option?

Post by Snakeoil » Fri Apr 10, 2020 8:30 pm

How did you end up with so many engines?
Regards,
Rob
Proud member of the Peanut Gallery
2000 Ural Tourist
40 Pilots, 122 Mains
Before you say something stupid, always ask yourself, "What would Harpo say?".

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Re: Crankshaft bearing shields: an option?

Post by Desantnik-VDV » Fri Apr 10, 2020 8:35 pm

Oil also lubricates rear seal around the shaft.
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Re: Crankshaft bearing shields: an option?

Post by Tomcatfixer » Fri Apr 10, 2020 9:40 pm

Desantnik-VDV wrote:
Fri Apr 10, 2020 8:35 pm
Oil also lubricates rear seal around the shaft.
This is true, and there will still be oil in the space between the bearing and the seal, especially if I notch the shield... just not as much oil. Will this increase rear main seal wear? Maybe. That's why I'm asking the Collectives' opinion.
How did you end up with so many engines?
- One 650 is from my '99 Tourist project bike. It has not yet run under my ownership, but it has a lovely shade of beige baked onto it.
- One 650 is from my '01 Patrol, which has developed some annoying oil leaks. It ran fine, but after tearing it down so far, Jaybird convinced me to just go ahead and replace the Russian crank & cam bearings while I was at it.
- The kickstart-only 650 is from the mystery vintage Tourist I recently acquired from eastbloc. It came with no cylinders installed. I'm guessing it's an early U.S. import.
- The shiny 650 crankcase, I received from a friend of BigJames. It arrived full of water, leaves, mud, and rust, but amazingly, the crankshaft spun freely and felt great (still gotta measure it, to see if it's salvageable).
- The 750 is a blown motor I bought off of a guy that decided to convert his Gear-Up to electric drive. It's the basis for my 825cc project. I've got the Big Russian Pistons, just gotta get a local machine shop to bore out the jugs.

I've also got the 2015 engine in the Mobile Chernobyl, but I'm hoping that I don't have to remove it any time soon. :wink:
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Crankshaft bearing shields: an option?

Post by Snakeoil » Sat Apr 11, 2020 1:30 pm

My 650 had an oil slinger that went on between the bearing and the seal. I inadvertently left it out because it was put in a bag with the old bearing. Found it after bike was running. Did you not find a slinger on the back of any of your 650 cranks? It's simply a sheet metal disc that slips over the crank.

Terry Crawford said not to worry about it. The new bearingI installed did not have a shield. It was an open bearing. I don't think the slinger did much as it was a truly awful fit on the crank. Terry said that BMW used a slinger like that on the /2 engines.

If I had to do it over again, I'd use the shielded bearing. Cutting a notch is not a bad idea. Allows some oil to get to the seal. Although I might just grease the seal.
Regards,
Rob
Proud member of the Peanut Gallery
2000 Ural Tourist
40 Pilots, 122 Mains
Before you say something stupid, always ask yourself, "What would Harpo say?".

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Re: Crankshaft bearing shields: an option?

Post by Tomcatfixer » Sat Apr 11, 2020 2:38 pm

Did you not find a slinger on the back of any of your 650 cranks?
All eight 650 and 750 crankshafts in my possession have oil slingers fore and aft.
If I had to do it over again, I'd use the shielded bearing. Cutting a notch is not a bad idea.
Thank you for your input.
- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

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Re: Crankshaft bearing shields: an option?

Post by petermertos » Sat Apr 11, 2020 4:06 pm

Tomcatfixer wrote:
Sat Apr 11, 2020 2:38 pm
If I had to do it over again, I'd use the shielded bearing. Cutting a notch is not a bad idea.
Thank you for your input.
Agree - cut a notch, it would be more than enough for oil to lubricate the rear seal.
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Re: Crankshaft bearing shields: an option?

Post by jeffsaline » Sat Apr 11, 2020 5:04 pm

I would probably consider using assembly lube when installing the bearing and seal. That takes care of the first minute or so after engine start up. I would also use the kicker to turn the engine to get the oil system primed prior to first start.

I don't know if the notch would make much difference or not but I sure wouldn't be opposed to notching.

Best,

Jeff
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2010 Gear Up
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Re: Crankshaft bearing shields: an option?

Post by Tomcatfixer » Sat Apr 11, 2020 5:20 pm

I popped the two metal shields off of a 750 crank bearing. I removed one side with a scribe and the other with a small flathead screwdriver and, as you can tell, it was difficult to do without bending the shield.

2020-04-11 17.11.45.jpg
2020-04-11 17.13.11.jpg
2020-04-11 17.14.09.jpg

I suppose I can re-flatten the portion of the shield I bent (I only need one shield) and attempt a notching and reinstallation. It's unfortunate that I couldn't pry it out of the bearing along the outer edge, because if I could, I would just create one of the notches where the bend was.

I wonder how well a notched rubber shield would hold up? It would be much easier to remove and cut.
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- Chad

Gordonsville, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 2001 Ural Patrol "Little Red Bear", 1999 Ural Tourist "The RPOC", Mid-Nineties Ural Tourist "The Heap", 1994 Honda VFR750F

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
Two different 1986 Yamaha FZX700S Fazers

jeffsaline
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Re: Crankshaft bearing shields: an option?

Post by jeffsaline » Sat Apr 11, 2020 5:23 pm

Can you try the tip of a knife blade? Metal shields are difficult sometimes.

Edit addition: Just had another thought. Can you just drill a small hole or two in the shield with it in place?

Best,

Jeff
Jeff Saline
2010 Gear Up
-Good, Fast, Cheap. Pick Two
-Just because something isn't true, no reason you can't believe it. Hub McCann Second Hand Lions
-Anything is possible if you don't know what you are talking about.

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Re: Crankshaft bearing shields: an option?

Post by BillyG » Sat Apr 11, 2020 5:57 pm

You don't need to notch anything. Pull one shield and leave the other alone. I did this on both crank bearings 150-200K km's ago. It don't hurt sh#t.
Last edited by BillyG on Sat Apr 11, 2020 8:50 pm, edited 1 time in total.
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300,000 km's since May 1st 2002
The "Unofficial Ural Service Manual" can be viewed at: http://www.myural.com

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