Author Topic: My non oil tight Honda  (Read 1009 times)

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Offline JBMorse

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My non oil tight Honda
« on: July 03, 2019, 04:32:13 am »
I recently stripped the top end on my beloved CB500K, hoping to find the source of excessive top end clattery noise. Long story short, I couldn’t find anything terribly wrong so I put it back together with new seals and gaskets. Before this, I had some oil weeping out of the valve cover in a couple places including the end cap o rings in the right side. Every so often I would wipe the top of the head clean with a rag.

So this time around, I tried to get smart and be very careful about the orings and gaskets. I made sure the new ones were clean and lubricated them with a little dab of red grease. After getting the engine all together and running it 100 miles or so, all looked well until this morning, when I noticed a slight film of oil on the horizontal top surface of the head, as though oil is seeping out of the end cap orings and collecting there. I looked real close and could see a slight bubbling around the right oring of the valve cover end cap. I also detected a slight film of oil under a couple of the valve inspection caps.

So what have I done wrong here? Overtorquing? Was the red grease the wrong choice to lube the orings?
Is it simply a matter of wrong oil choice? I’m using 15w40 Rotella, but the temps are getting into the 80s here in New Hampshire.
I used the “NE” brand gasket set from 4into 1. It seemed to be of good quality.

Interestingly, these are the same couple places I seemed to get leaking last time.
Thanks and I hope you all can help alleviate some frustration!
« Last Edit: July 03, 2019, 06:57:08 am by JBMorse »
1971 CB500K

Offline uksparky

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Re: My non oil tight Honda
« Reply #1 on: July 03, 2019, 06:52:03 am »
NE brand O rings/rubber gaskets  ::)  when the engine is cold the oil pressure will be higher pushing it past the end cap seals... the red grease would not cause the leak, now it could be the O ring quality ... i had the same problem with NE valve cover gasket and end cap O rings leaking, the OEM is a much better fit, that's what i have installed now, so far the NE head and base O rings are ok that i fitted few years back...... i use  Castrol 20/50 motorcycle oil with no leaks..
« Last Edit: July 03, 2019, 06:58:15 am by uksparky »
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Offline bryanj

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Re: My non oil tight Honda
« Reply #2 on: July 03, 2019, 07:31:43 am »
Under the end cap is a steel bracket, the bolt that holds that bracket on should have a soft alloy washer between the bracket and the valve cover or you get an oil leak! Frquently gets lost or swapped for a sreel one both causing a leak.
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline JBMorse

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Re: My non oil tight Honda
« Reply #3 on: July 06, 2019, 05:26:39 am »
Thanks guys,
I will double check that those washers are in place in the valve cover end cap. What I might do is compile a small list of the part numbers for all my leaking o rings and order OEM ones from Honda. Maybe that will be my answer! I can't think of any other reason they wouldn't be sealing up and it's only a couple of them that are leaking.
1971 CB500K

Offline rotortiller

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Re: My non oil tight Honda
« Reply #4 on: July 06, 2019, 05:55:26 am »

Offline bryanj

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Re: My non oil tight Honda
« Reply #5 on: July 06, 2019, 08:50:32 am »
Not in that position, tried it didnt work
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!