Author Topic: Oil leak help and sense check.  (Read 286 times)

Offline Dolomite_

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Oil leak help and sense check.
« on: May 25, 2019, 04:55:19 PM »
So there is an oil leak coming from the bottom of the barrels around where the oil breather dowel is. After taking the barrels off the gasket is nackerd and seems to be split where the dowel is (pic 1 and 2) so I'm thinking that could be the reason for the leak.

Now for the sense check. After having a look at the CB400 four engine rebuild that Nurse Julie posted it seems like the little o-rings that go around the dowels werent there (pic 3). So it seems to be a combination of both the gasket and the o-ring. I plan on replacing the gasket, obviously, but couldnt find the little o-rings for the dowels on davidsilvers, unless I missed them. Could someone point me towards them? They definitely should have the o-rings for the dowels right? I couldnt find any mention of the o-rings in part diapgrams I've been looking at.

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: Oil leak help and sense check.
« Reply #1 on: May 25, 2019, 05:12:17 PM »
That's a main oil return path from the crank to the camshaft.. You won't find the O ring in any gasket set or a part number as it is not a standard part, it is an 'upgrade' that helps prevent oil leaking from the return path and getting under the gasket causing the base gasket to leak. If I can remember what size the O ring was that I fitted, I will let you know.
What has happened to your base gasket is exactly what I have described above.
« Last Edit: May 25, 2019, 05:16:06 PM by Nurse Julie »
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: Oil leak help and sense check.
« Reply #2 on: May 25, 2019, 05:20:44 PM »
In fact, the closer I look, it actually looks like that gasket was split when fitted, its not sitting right at all. 🤔 And, someone has been there with a flat blade it screwdriver by the looks of it 🤔🤔
« Last Edit: May 25, 2019, 06:17:48 PM by Nurse Julie »
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline mattsz

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Re: Oil leak help and sense check.
« Reply #3 on: May 25, 2019, 05:37:43 PM »
Mysterious - pics 1 and 2 don't show on my computer... only #3...

Offline heliwilly

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Re: Oil leak help and sense check.
« Reply #4 on: May 25, 2019, 05:54:17 PM »
Only pic #3 on my PC as well???   Bill W

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: Oil leak help and sense check.
« Reply #5 on: May 25, 2019, 06:03:28 PM »
All 3 pics showing on my phone.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline mattsz

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Re: Oil leak help and sense check.
« Reply #6 on: May 25, 2019, 06:32:28 PM »
You can see them, that's what counts, Julie!  He's getting the help he needs from you.  I'm just hanging about...

Offline Dolomite_

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Re: Oil leak help and sense check.
« Reply #7 on: May 25, 2019, 10:27:35 PM »
In fact, the closer I look, it actually looks like that gasket was split when fitted, its not sitting right at all. 🤔 And, someone has been there with a flat blade it screwdriver by the looks of it 🤔🤔

Dont know how long the last owner had this gasket on but it ripped in quite a few places when  I took the barrels off. It does look like a flat head has been at it :D but it's just where its ripped

 

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