Sudden oil leak

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
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Here is the place for you to ask questions about or share your experiences about servicing or repairing your Ural or Dnepr. Please post topics concering modifications or accesories in the "Modifications and Acessories" section. Please post oil related questions in the "Oil Threads" section.
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HassoBoxhead
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Sudden oil leak

Post by HassoBoxhead » Sat May 18, 2019 5:35 pm

Yesterday when I arrived home from my daily commute to the Pentagon, I parked in the driveway and went inside. Came out 10 mins later and notice a Skitch oil spot the size of a softball underneath the engine.

Looked to see where the oil dropped from and it look like the back of the engine above the starter (sorry, not tech savvy). So I started it up and let it run at idle in the driveway for 10 mins and no more seepage.

Took a ride to fill up the tank and came back and parked...drips of oil spatter on the driveway and eventually stop when about the softball size.

I can’t pinpoint where it’s coming from (visibly) so I don’t know how to address the issue.

Prior to yesterday not a drop since I’ve owned it. No change to route or riding style, don’t know why this happened all of a sudden.
CA170A45-7E33-477C-857E-CC0A7C91580B.jpeg
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Tomcatfixer
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Re: Sudden oil leak

Post by Tomcatfixer » Sat May 18, 2019 8:41 pm

Crankshaft rear main seal?
- 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

HassoBoxhead
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Re: Sudden oil leak

Post by HassoBoxhead » Sat May 18, 2019 10:45 pm

Since it only happens when the rig is on the road ( not just idling in the driveway) could be that rear seal.
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jeffsaline
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Re: Sudden oil leak

Post by jeffsaline » Sat May 18, 2019 11:31 pm

Clean the oil from the exterior of the engine. Dry the area and then spray foot powder where you think the leak is originating. Ride the machine stopping every minute to look for the leak. The leak will darken the foot powder. Continue the ride for a minute, stop and look routine until you find the leak.

Also remember to check the oil level to make sure the engine isn't running low.

When I was a test rider I had one machine I had to ride 30 miles to locate the leak. It took the technician about 15 minutes to repair once I told him where the leak was originating.

Good luck and best,

Jeff
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Mr Wazzock
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Re: Sudden oil leak

Post by Mr Wazzock » Mon May 20, 2019 7:10 pm

Looking at the photos properly, seems like it's coming from high up so I don't think it's rear crank seal.

Looks like could be crankcase breather hose is loose on the air filter coupling? Altho, nonetheless, it shouldn't be blowing too much oil unless it's overfilled or you're frequently doing high revs. (?)
Mike H
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(aka Oranzhevaya Opasnost, "The Orange Peril")

HassoBoxhead
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Re: Sudden oil leak

Post by HassoBoxhead » Mon May 20, 2019 11:19 pm

I do highway speeds and did a slight overfill, but why would it continue to flow after it loses almost half?
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Lokiboy
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Re: Sudden oil leak

Post by Lokiboy » Tue May 21, 2019 6:53 am

If you overfilled, there is a possibility that you just have excess oil going into the air-box as Mr. Wazzock discribed. Remove and clean the air box, then clean around the area. Keep an eye on it.
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
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HassoBoxhead
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Re: Sudden oil leak

Post by HassoBoxhead » Tue May 21, 2019 7:39 am

Thanx for the suggestion on the air box, is there a video/link that describes how to remove it?
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Mr Wazzock
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Re: Sudden oil leak

Post by Mr Wazzock » Tue May 21, 2019 6:21 pm

Actually there shouldn't be any oil in the filter box, on account of there's branch pipes inside that direct the breather outlet directly into the throttle body intakes to be burnt in the engine.

Secondly, there's a small drain hole at the back (left of attached photo) so any substantial amount in there would come out of there, and that's at the back of the filter housing, not the front where the oil is showing externally. If the engine breather hose is loose on the air filter coupling it could do that tho. However this may all be academic if substantial amounts of oil is being lost from the sump.

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Air Filter 001.jpg
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Air Filter 002.jpg
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Air-filter-box.jpg
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To remove the air filter cover, take out the 4 screws. Loosen the cover by prizing upwards on both sides. The wiring harness under the frame may be in the way. It was on mine. A couple of zip ties had to be cut so I could move it and press upwards enough to make room for the filter cover to move up off the housing. Next, you wll need to "unstick" the actual filter element from the cover, with a screwdriver. When the filter is dropped back down in the housing, then the cover can be removed by sliding it out sideways. Which side depends on which side the harness is attached to the frame, on mine it leftways because the wiring harness is on the right side of the frame.

When cover is off, fliter element can be lifted out and, ditto, slid out sideways.
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Martin74Olofsson
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Re: Sudden oil leak

Post by Martin74Olofsson » Tue May 28, 2019 3:49 pm

Hello
I have got the same problem on my 2018 gear up with 16000 km on it. The engine is out and it is the rear crank seal.
You can remove the rubber plug on the right side of the engine(the plug for the tdc) if there is oil it is most certainly the rear crank seal.
God luck
Martin O

HassoBoxhead
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Re: Sudden oil leak

Post by HassoBoxhead » Sat Jun 01, 2019 6:18 pm

Finally got it to a repair shop today. He’s still evaluating, but most likely a main seal.
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Retired Air Force Russian Linguist
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HassoBoxhead
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Re: Sudden oil leak

Post by HassoBoxhead » Thu Jun 27, 2019 5:33 pm

Just got the evaluation from the mechanic:

it looks as if the flywheel is the cause of the oil leak. The seal has
cut a grove into the sealing surface that is not consistent all the way
around. The clutch discs are soaked with oil. I would also replace the
transmission input shaft front seal since we have ready access to it.
2014 Slate Grey Gear Up «Миша»
Retired Air Force Russian Linguist
“Too Close for Missiles, Switching to Guns”

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Lokiboy
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Re: Sudden oil leak

Post by Lokiboy » Thu Jun 27, 2019 6:27 pm

What’s causes the seal to fail?
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
100,000 km and counting

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Mr Wazzock
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Re: Sudden oil leak

Post by Mr Wazzock » Fri Jun 28, 2019 3:21 pm

Bum. :(
Mike H
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