Author Topic: Oil passage o rings and others  (Read 1501 times)

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Offline needswork

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Oil passage o rings and others
« on: January 05, 2008, 11:46:34 AM »
My bike always leaked oil between the two cylinder halves near the rear. I suspected that the gasket there was the culprit. I tore down the engine to find that the gasket looks like new, no tears or anything  >:(. During this tear down, while removing the cylinder, I found the o-ring for the oil passage beside cylinder #1, but I couldn't find the o-ring for the passage beside #4. If there wasn't an o ring there, that would explain the leak (assuming that was the cause, I sure hope that was).
I used the Honda shop manual I downloaded on another web site. I don't think I want to go any further with the teardown but start putin' her back together.

Anyway, a couple of questions;
1) The o-ring mentioned above is green (is that right?). Can I just buy an o-ring at canadian tire that would fit? I've replaced a bunch of o-rings on this bike already with 10 cent o-rings from CDN Tire.
2) Is there a trick to getting the nuts back on the studs (beside the spark plugs)? Looks like a PITA job.
3) I can only find 8 washers (and there are 12 studs), shouldn't there be 12 washers?
4) Any other advice?
'78 CB 550K fixer-upper. The bike needs work, I sure don't!

Offline 05c50

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Re: Oil passage o rings and others
« Reply #1 on: January 05, 2008, 03:07:46 PM »
Ok,
  The fact that the o-ring is green is a warning that the engine has been apart before,but you probably already figured that out because there should be 2 o-rings. Green o-rings started to show up about 15 years ago and are used on car air conditioners alot. The Honda part # is 91310-426-000 and are still available,but for a little more then the average o-ring. I just ordered some today. Since it's a pretty big job to get to these o-rings, I don't think I'd pinch pennies now, but they are 11x2.5 mm. if you want to try another source.
  To get the nuts back on,stick them into the socket with something sticky (gum,silly putty etc.) or use a tooth pick as a guide and drop them onto the stud/I've done it both ways.
   There should be a washer on each stud. Use heavy washers to replace missing ones.
   As for other advise....you might want to consider pulling the jugs off as there are 2 o-rings under them (the same as the ones your working with) that may have been disturbed by loosening the head studs,or worse still-left out by the po.
Good luck

........Paul
Wear a helmet,the life you save may be your own.Ask me how I know.               CB650C,CB550F,GL1000,CB750A

Offline needswork

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Re: Oil passage o rings and others
« Reply #2 on: January 05, 2008, 04:40:42 PM »
Thanks Paul,

I figured someone had been there before too. You're right about not penny pinching now, I'll order some new o-rings on Tuesday (bike shop is closed 'til then).
Thanks too for the advice about getting the nuts back on (I think I'll be chewing gum during the re-build  ;D). Can I lift the jugs just enough to replace those bottom o-rings without getting into removing the pistons etc...?
Thanks again.
'78 CB 550K fixer-upper. The bike needs work, I sure don't!

Online bryanj

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Re: Oil passage o rings and others
« Reply #3 on: January 05, 2008, 05:19:40 PM »
you will need a new base gasket and a new head gasket as well as the O rings. These gaskets CANNOT be re-used
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 needswork

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Re: Oil passage o rings and others
« Reply #4 on: January 06, 2008, 02:04:27 PM »
Thanks bryanj.
I think I'll leave the jugs in place, the gasket I "removed" still looks as good as new so I'm going to put it back. I think the oil leak was from either the missing (?) o-ring at the oil passage or else the stud nuts weren't torqued down well.
'78 CB 550K fixer-upper. The bike needs work, I sure don't!

Offline Dave Wyatt

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Re: Oil passage o rings and others
« Reply #5 on: January 07, 2008, 07:16:33 AM »
I just replaced the head gasket and O-rings on my 'matic.  My original O-rings all "looked" good, but were old and stiff.  The head gasket, had it been doing it's job, would not have been letting oil seep out to begin with, so it got replaced.  Mine appeared to be wicking oil out from the oil passages.  The first clue to the well being of the head gasket was, the head came off with ease, since the gasket wasn't stuck to well, and it should have been.  I will guess that your head gasket is shot, in spite of how it may look. 

The new head gasket was made by Victor-Reinz (sp?) which makes gaskets for many applications and is a good brand.  I doubt I'll be going back in there anytime soon.

I put the nuts back on the studs near the spark plugs with two fingers.  The plugs were out, so I had some room. 
Dave Wyatt
1976 CB750A
1965 C100
2008 GL1800
I swear, the damn things are starting to breed!

Online bryanj

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Re: Oil passage o rings and others
« Reply #6 on: January 07, 2008, 08:31:28 AM »
DO NOT re-use the gasket or you will be doing the job again soon.

Also I guarantee the base will start to leak soon after you have struggled the lump back in----It really is VERY false economy not to chasnge ALL the gaskets AND rubber bits from the base upwards-----But What the $^*& its your time (Spanner and riding) and Cash
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 needswork

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Re: Oil passage o rings and others
« Reply #7 on: January 08, 2008, 10:18:07 AM »
hmm... you guys haven't given me a lot to think about... :-\ But thanks again.
'78 CB 550K fixer-upper. The bike needs work, I sure don't!

Offline Dave Wyatt

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Re: Oil passage o rings and others
« Reply #8 on: January 09, 2008, 10:16:02 AM »
hmm... you guys haven't given me a lot to think about... :-\ But thanks again.

Sorry you feel that way, but based on experience it's pretty simple.  Replace all the gaskets and O-rings, or do it again soon.  I used a Versah gasket kit that had everything I needed in it.  Had some extra stuff too, but thats the best I could do for my 'matic.  I'd suggest a kit and use what you need. 
Dave Wyatt
1976 CB750A
1965 C100
2008 GL1800
I swear, the damn things are starting to breed!

Offline needswork

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Re: Oil passage o rings and others
« Reply #9 on: January 10, 2008, 11:38:27 AM »
Don't apologize for being helpful Dave.  I meant to say "have given me a lot to think about" not "haven't given..." my bad.

It makes sense that I've gone this far, I should go a little further and do the job once/right rather than do this all over again next year  >:(.  I guess I'll look around for parts or kits.

Thanks again everyone.

Paul
'78 CB 550K fixer-upper. The bike needs work, I sure don't!

Offline Burke

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Re: Oil passage o rings and others
« Reply #10 on: January 10, 2008, 12:44:56 PM »
So if one is to replace the head gasket, the base gasket is sure to go? ???

Offline Bodi

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Re: Oil passage o rings and others
« Reply #11 on: January 10, 2008, 12:54:06 PM »
"So if one is to replace the head gasket, the base gasket is sure to go?"

There's no guarantee, but it is likely to leak. You're certain to disturb the base gasket seal when you pull the head off. Installing a new one isn't a huge extra job and you get a look at the pistons and rings, always useful.

Offline Burke

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Re: Oil passage o rings and others
« Reply #12 on: January 10, 2008, 05:34:47 PM »
good info  :)

Offline needswork

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Re: Oil passage o rings and others
« Reply #13 on: January 11, 2008, 06:16:10 PM »
Burke,
I'm not replacing the head gasket but the cylinder gasket (I think!). The gasket below the intake and exhaust ports, that's the one that leaking anyway.
'78 CB 550K fixer-upper. The bike needs work, I sure don't!