Author Topic: burning oil. head off to do valve seals but...  (Read 2642 times)

Offline Graeme77

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burning oil. head off to do valve seals but...
« on: November 07, 2015, 05:14:37 PM »
As title.
valve seals seem ok, all dry except number 4 which had lots of oil in the bore. So I know why its smoking on start up but dont know why there is oil in the bore.
The oil seems to be coming from around the stud and leaking past the head gasket. Its number 13 stud in the tightening order. It doesnt have an o ring so im guessing there shouldnt be oil here to start with? With the head off its still full of oil around that stud so is it just going to be getting past the nut and washer? Can oil come up around this stud? Can it drain away from this stud?
I can see no obvious problems with any seating surface and all torques were good.

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #1 on: November 07, 2015, 05:18:31 PM »
One other thing, the 8 studs that hold the cam towers, should they all be studs? 2 of mine are bolts, and they have stripped the thread in the head. Ill helicoil it so not too big a deal but just wondered.
Oh, and while im at it, should the 6 10mm head bolts be tight? Mine werent. Its been apart before obviously but not by me. I have a photocopy of the factory manual but its a but vague.

Thanks.

Offline bytio

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Re: burning oil. head off to do valve seals but...
« Reply #2 on: November 07, 2015, 05:37:09 PM »
Only 4 should be studs on cam towers,. These need to be thread sealed as oil will leak past them because the holes go to the outside world!

Offline Trigger

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Re: burning oil. head off to do valve seals but...
« Reply #3 on: November 07, 2015, 05:42:02 PM »
What 750 engine would be a great clue as the K has many differences and the F has a couple of differences. Any pictures ?

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #4 on: November 07, 2015, 05:52:32 PM »
Sorry, 750f1 1976.
I can take pics of anything you need, ill take a few general onesbin a bit.

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #5 on: November 07, 2015, 05:59:40 PM »
Pics hopefully.

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #6 on: November 07, 2015, 06:00:59 PM »
One at a time it seems

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #7 on: November 07, 2015, 06:01:46 PM »
:)

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #8 on: November 07, 2015, 06:02:29 PM »
:)

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #9 on: November 07, 2015, 06:03:15 PM »
:)

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #10 on: November 07, 2015, 06:04:51 PM »
Ive wiped most of the oil away but you can see it around the stud. Number 4 is suspiciously clean. There wasboil from thebstud hole to the bore on both sides of the gasket and oil in the bore.

Offline Chris400F

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Re: burning oil. head off to do valve seals but...
« Reply #11 on: November 07, 2015, 06:54:53 PM »
One other thing, the 8 studs that hold the cam towers, should they all be studs?
I've found with my bikes that the Parts Lists are really helpful for working out what parts you should have.
There looks to be one for the 750 F1 in Ashimoto's Dropbox: http://www.sohc.co.uk/index.php/topic,8884.0.html

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #12 on: November 07, 2015, 06:57:34 PM »
Good point, I have a genuine parts book somewhere.

Offline Spitfire

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Re: burning oil. head off to do valve seals but...
« Reply #13 on: November 07, 2015, 07:08:09 PM »
Between 1&2 and 3&4 there should be 4 dowels and sleeves, those look like O rings on yours, and has already been said there should only be 4 studs for the cam towers.


This should show it better


Cheers

Dennis
« Last Edit: November 07, 2015, 07:11:08 PM by Spitfire »
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Graeme77

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Re: burning oil. head off to do valve seals but...
« Reply #14 on: November 07, 2015, 07:21:41 PM »
I guess the cam tower stud thing doesnt really matter, as long as it all bolts down right.
just had a look and I have all the hollow pins and right seals forbthe studs, just dont know why this end stud is full of oil.
I guess it must be coming down from the nut and washer. Head gasket obviously isnt stopping it getting into the bore.
Should the head washers and nuts be sealed?

 

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