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Author Topic: Oil leak where header meets engine.  (Read 3475 times)

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Offline Tarmac

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Oil leak where header meets engine.
« on: March 18, 2014, 03:54:47 PM »
As the subject states, i've got oil around the nr1 header on my K7 CB750. Enough to make a small 1X2" stain on the floor beneath it. I guess a new crush gasket would do the trick, but not fix the source of the problem. Any ideas on what the problem is and what I should do to fix it?
Thanks!
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Offline goldarrow

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Re: Oil leak where header meets engine.
« Reply #1 on: March 18, 2014, 04:05:31 PM »
My engine leaked around exhaust port #3, changed fork seals and now no more leak.  Weird, huh, I know...
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Offline grcamna2

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Re: Oil leak where header meets engine.
« Reply #2 on: March 18, 2014, 04:24:13 PM »
Welcome to the forum Tarmac !
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Re: Oil leak where header meets engine.
« Reply #3 on: March 18, 2014, 04:52:10 PM »
Tarmac Welcome
  goldarrow has a point in case there is a language barrier he means the leak could be coming from somewhere else and the wind is blowing the oil up there. So get some engine cleaner and get everything good and clean. Some like to use baby power and put it all over the area to see for sure where it is coming from. Then we can go from there.
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Offline Tarmac

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Re: Oil leak where header meets engine.
« Reply #4 on: March 18, 2014, 10:19:40 PM »
Thank you! Have been lurking since I got a CB500 some years ago.

I'm very sure it's not from the forks, since it was idling outside the shed. Have noticed the leak before after riding but couldn't locate the leak  before.
Since it's not charging the battery I've only taken a few very short rides on it :)


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Offline Tarmac

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Re: Oil leak where header meets engine.
« Reply #5 on: March 18, 2014, 10:23:05 PM »
...will do as suggested though to be sure. Thanks :)


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Offline ncstatecamp

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Re: Oil leak where header meets engine.
« Reply #6 on: March 18, 2014, 10:28:27 PM »
can you tell the gasket the leak is coming from? I had a thing that looked like a head gasket leak but it was a puck under the cam holders.
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Offline Tarmac

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Re: Oil leak where header meets engine.
« Reply #7 on: March 25, 2014, 11:35:55 AM »
Ok, wiped everything off and did some 0kmh racing in the shed. Looks like a leaky head gasket. If so, while pulling the thing apart, what do you think I should do while the engine is out and apart? Apart from the obvious head gasket. And speaking of gaskets, are the Athena sets any good? Can get my hands on those cheap.


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Offline ncstatecamp

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Re: Oil leak where header meets engine.
« Reply #8 on: March 25, 2014, 11:49:15 AM »
I had the exact same thing, again, not necessarily a head gasket. I just finished a top end rebuilt, used cyclex gasket kit. So far no leaks and the kit had everything except a few o rings I had to hunt down on amazon. While I was in I measured everything I could. What my build ended up being was

New head gasket (kit)
New base gasket (kit)
Lapped valves
New rings
New o rings
New valve guides (kit)
New chain tensioner guide & wheel
Honed cylinders
Cleaned the piss out of every nook n cranny


Before going to all that length the first I'd recommend would be to do a compression test, and if that comes back sour do a leak test to see where loss is. After opening it up, just measure everything for tolerance (depending on what your tests conclude). Also I think cycleX is the only one with pucks in it... But I may be wrong.
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Offline MCRider

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Re: Oil leak where header meets engine.
« Reply #9 on: March 25, 2014, 11:56:17 AM »
Tarmac: #1: CB500s can be worked on in the frame, don't need to take it out.

#2: Could be just retorquing the head nuts will fix the head gasket leak. Works on CB750s.

New pucks for good measure.
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Offline grcamna2

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Re: Oil leak where header meets engine.
« Reply #10 on: March 25, 2014, 02:19:50 PM »
Quote from: Tarmac on March 25, 2014, 11:35:55 AM
Ok, wiped everything off and did some 0kmh racing in the shed. Looks like a leaky head gasket. If so, while pulling the thing apart, what do you think I should do while the engine is out and apart? Apart from the obvious head gasket. And speaking of gaskets, are the Athena sets any good? Can get my hands on those cheap.


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Tarmac,
Get a Vesrah gasket set,they are the best I have ever found and as comparable to Original Honda as you can get. Quality matters. Anything is better than Made in China  :(
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75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline Don R

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Re: Oil leak where header meets engine.
« Reply #11 on: March 26, 2014, 04:50:55 PM »
It could be the head gasket but under the rocker stands are the 6 rubber nickel washers. They are usually the culprit.
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