Author Topic: F2 head leaking evidence in pics what now?  (Read 1947 times)

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Offline Ace

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F2 head leaking evidence in pics what now?
« on: May 30, 2009, 09:05:37 PM »
I degreased the engine and then ran it for about 10 mins varying the revs.  I took the engine out and dusted it with athletes foot powder so I could see the oil on the engine.  Makes it easier to see on a black engine.  I put power between #2/3 cylinders for comparison both front and back.  As you can see in the pictures the power has stuck to the oil.  Now I have to work out where exactly all the oil is coming from.  The bike was run on the center stand to avoid oil being blown through the fines.  Looks like a possible leak from the tappet cover and somewhere else.  Since the front of the engine leans slightly forward, the oil runs towards the front of the bike.  From what I can see, it's a tad hard to get the oil from the tappet cover to run up to the air intake side of the engine and around the spark plug etc.  Any thoughts?
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline MCRider

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Re: F2 head leaking evidence in pics what now?
« Reply #1 on: May 30, 2009, 09:21:36 PM »
A little hoousekeeping: this should not be in "projects" which is for complete bike projects. "SOHC4" if the better place. It will likely be moved soon.

If your oil is appearing in fins between the cam cover gasket and the head gasket, it is likely coming from two places. THe rubber pucks under the cam towers, or the threaded holes which are open to the atmosphere and through which the holddown stud/bolts for the cam towers are threaded.

If its the pucks, well there you go. New pucks, layers of sealer.

THose threaded holes are the b--stards. Has your head been apart, have those holes been stripped and repaired, helicoil?

We just had a big thread on this lately.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline mazingerzeca

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Re: F2 head leaking evidence in pics what now?
« Reply #2 on: May 31, 2009, 02:47:41 AM »
I had the same problem. Take a look at this http://forums.sohc4.net/index.php?topic=51534.0

Offline Ace

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Re: F2 head leaking evidence in pics what now?
« Reply #3 on: May 31, 2009, 06:25:53 AM »
Your F2 head is different to mine   ;D.  Look at the difference between the two exhaust valves  (#1-2) and (#3-4) : mine has a passageway between them and yours is blocked.  I think it could be the same between the valves on the intake side as well.  Now the question is, are they both F2 heads or is one an imposter? 

K heads on F2 barrels I didn't think worked real well....Either way, I hate oil leaks....

For mine, it looks like the penny washer and possibly somewhere else which I'm yet to find out.  A lot of helicoils in my F2 head.  First time I've pulled it all apart, fun though.  I just hope it all works like it should when I put it together.
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline mazingerzeca

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Re: F2 head leaking evidence in pics what now?
« Reply #4 on: May 31, 2009, 06:54:18 AM »
If 410 is written on the back top fin, is a F2 head, as far as I know. My head has a lot of helicoils too. I'm almost sure that this is the way that the oil finds to the atmosphere. I've just bought a spare head. If you can not find a way to seal these passages, you will have leaks. Not sure about yours, but if after replacing the penny rubbers, it leaks, maybe it through the front helicoiled threads.

Offline MCRider

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Re: F2 head leaking evidence in pics what now?
« Reply #5 on: May 31, 2009, 01:49:26 PM »
If 410 is written on the back top fin, is a F2 head, as far as I know. My head has a lot of helicoils too. I'm almost sure that this is the way that the oil finds to the atmosphere. I've just bought a spare head. If you can not find a way to seal these passages, you will have leaks. Not sure about yours, but if after replacing the penny rubbers, it leaks, maybe it through the front helicoiled threads.
Would it be "capillary action"? but however, the oil is just drawn to those heli-coiled holes and if they are bottomless, they will leak to the atmosphere. Very frustrating.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."