Topic: CB550 - valve cover gasket issue - now with PICS

[AMT]

Hey guys. Did some work to my '74 CB550 this winter - new gaskets and O-rings from the head gasket up and a bunch of routine maintenance that had been overlooked for some time. Got the bike back together last week and it runs beautifully... except for a pretty significant oil leak that appears to be coming from the exhaust side of the valve cover near cylinder #1, and also the cylinder #2 tappet cover. Twice around the block and I've got oil running down the fins... its leaking pretty good.
I've read a bunch of threads on oil leaks... which all read about the same: New gasket, re-torque, ride on.

The valve cover gasket and tappet cover gaskets are from a Vesrah kit, and I replaced the valve cover screws with stainless allen head bolts and torqued to spec (7 lbs I think?) the spec allowed for 1 or 2 more lbs but the short length of the bolts really made me nervous to go any further...

I guess my question is... the cover was not leaking with the old gasket & bolts... and is now leaking with the new gasket and bolts. Is there any reason to assume the vesrah gasket is bad and needs to be replaced with OEM? The fact that it's leaking from two places makes me feel like the internal pressure may be higher than normal, but I can't think of any reason for that to be true. Does that seem like a probable cause?

[dave500]

theres no real pressure behind there,probably the rubber gasket is slightly smaller in diameter than its supposed to be?,dont over tighten any 6mm bolt,they strip the thread trying to use a torque wrench,just feel them down with a strangled spanner,if the leak is pissing out youll have to remove the cover again,ive sealed them when a gasket wasnt handy by cleaning and drying the groove out,then running a bead of decent gasket sealer neatly around in the groove and letting it cure for 45 mins,then refit it,thats how my sump  pan is sealed!

[Duanob]

did you replace the pucks? They get old dry and brittle.

[AMT]

Pucks are also new. The valve cover gasket from vesrah seemed to fit pretty well.. I don't have a new OEM one on hand, but I may actually try the old OEM gasket from before the top end job just to see if it'll get me through the weekend. I can't imagine the old gasket sealing better than the new one but who knows. Wasn't sure whether I'd actually see anybody recommend gasket maker but I was considering it. Thanks for the tip on the 6mm bolts... I used a torque wrench and it was a pretty terrifying experience... I was really afraid to strip them because the sense of feel is pretty tough at that point.
I had read something about a blocked breather tube causing high pressure in the head... I suppose that's worth checking out.

[dave500]

yeah be sure the breather tube is clear,those mud wasps can plug any opening,my mates weed whacker had no start,totally mud blocked exhaust.

[Stev-o]

Something's wrong, looks like you'll need to pull it off.
At least you don't need to pull the engine.

[AMT]

Something's wrong, looks like you'll need to pull it off.

Well you nailed that one on the head Stev-O.
Pulled the valve cover off tonight... and was happy to find the problem staring right back at me. Happy because it's no longer a mystery... although a bit disheartened to see what I saw:
Most of the mating surface / gasket trough looks great, much like picture number 1... however, Pictures number 2 and 3 show the ugliness I fund under... you guessed it.. the CYL 1 & 2 tappet cover areas. I have no idea how the PO managed this one... or how I managed to overlook it when putting back together, but I need to fix it and I'm not sure what to do. Some kind of gasket maker seems like the immediate fix (although maybe a new valve cover will be necessary down the road?) but I'm not familiar and there's 100 different kinds.
Recommendations on a brand / type that's good with a rubber gasket, high temp, aluminum mating surfaces, oil, etc?
Should I put it underneath the gasket to fill in all of those nasty pits, or just on the surface over top of the gasket... or on the mating surface of the cylinder head? Any advice would really be appreciated, and THANKS for the help already given.

[Stev-o]

Oh #$%*e, not good.  I would be very reluctant on using gasket maker, if it fails and ends up in your engine, it could clog oil passages and you'll have a major problem. Since I haven't done this, I will not give you any suggestions. Do some research before moving forward.
Good luck.

[AMT]

Thanks Stev-o.
No advice is better than bad advice. I was pretty shocked when I saw this and I have been struggling to come up with any ideas on how it could have happened. I've always understood gasket sealants and silicones and the like to be an unnecessary tool if you build things correctly... but I don't see any way around it in this particular instance without replacing the valve cover. I'm not opposed to doing this, but she's running so nice right now and I'd really love to ride it in the mean time. I can't imagine it getting into the engine if I applied it and let it set a while underneath the gasket, and then tightened it down, as it'd effectively be trapped within the gasket gully. Then again, I'm only imagining this to be true, which is why i'm looking for help here in the first place.

EDIT:
Also, I know there are some gasket sealants that are non-setting/non-hardening.. which should be safer for this application, but I'm really hoping somebody will chime in who has used a particular kind with good results.

[dave500]

id use silicone gasket maker and let it skin over for 45 minutes before you assemble it,no excess should get where it shouldnt then.

[Bru-tom]

what about taking a large piece of sandpaper on a sheet of glass (or any perfectly flat surface) and rub the bottom of the valve cover on it to smooth any high spots off. Its obviously not sealing there because of an uneven surface.

just an ideal. or firstly, take a flat edge and place it across the area in question and if you see any light, thats your problem area right there. what i would so is add some very thinned paint on there, give it a rub on a flat surface with a light grit sand paper and see where the high spots are and work from there...

[dave500]

i draw file high spots off those,and heads and barrels.

[Bru-tom]

i draw file high spots off those,and heads and barrels.

filing a surface like that takes practice to get them flat, i am a  millwright and have had lots of practice, damn apprenticeship anyway, i reckon sanding is a novices best bet, not?

[RAFster122s]

Is the mating surface uneven or is the groove pitted and deteriorated from corrosion? I think the later since it impacts the depth of the seal causing the problem.
Would a "fix" be to use some metal filled JB Weld and a Oring gasket lubed with a coating of grease to prevent the epoxy from adhering to the gasket? The idea being to restore the groove so the gasket is consistently expanded. I haven't had the cover off my head, is the groove a half moon rounded surface or square section groove?
The silicone gasket maker is probably a better kludge but it needs to be applied sparingly to not have slivers clogging oil passages if/when they break free.

[Stev-o]

Is the damage on the cover or the head? Or both??

[bryanj]

Forget the gasket maker/silicone/whatever and forget sanding That groove has been butchered by a PO and the only fix is a good used cover

[AMT]

Forget the gasket maker/silicone/whatever and forget sanding That groove has been butchered by a PO and the only fix is a good used cover

Bryanj, While I feel you're ultimately correct... I'm still going after a safe temporary solution until I source a nice used valve cover.

Is the damage on the cover or the head? Or both??

The damage is strictly on the valve cover.

Is the mating surface uneven or is the groove pitted and deteriorated from corrosion?

The mating surface appears to be fine, the issue is that the groove has been butchered and the gasket no longer fills it, allowing oil to flow into the groove and around the gasket. I like your JB weld idea... seems like a very interesting fix.. Just not sure this cover is worth the effort. +5 bonus points for using the word 'kludge' - one of my favorites for this type of situation. 

id use silicone gasket maker and let it skin over for 45 minutes before you assemble it,no excess should get where it shouldnt then.

This is the route I'm leaning on most heavily at the moment. I can't imagine this stuff breaking down in such a short amount of time that it'd really be dangerous... I intend to actively begin looking for a valve cover, and in fact have found one on eBay currently at around $55 shipped. Dave500, would you put the silicone sealer into the gasket groove essentially filling the pits much the way you would with the JB weld idea, and then lay the gasket into the groove after 45 minutes, or lay the gasket in and then fill the remaining space around it with the sealer?

Thanks again everyone.

[bjbuchanan]

Permatex ultra black is a silicone gasket maker that I have used pretty successfully. Let it it skin over like Dave said and then set everything up. The ultra black is the oil resistant good one. The key to using the stuff, if you have to, is to use it in a smart way. Clean up the surface well, no oil and wipe a thin bead in there and work from there. It stays really rubbery and sticks well. Just make sure there are no straggling swipes and crap like that that could flake off

The jb weld idea would work but you have to get the surface real clean because any oil is gonna make the jb weld stick so so after some heat cycles it will almost kinda float there. Given the fact it would be in that channel and held in place it would probably be fine tho. It is gonna be a little shaping and sanding tho. Still have to be careful with that one too tho so you don't have flakes and other crap fall off

[Stev-o]

No brainer - buy a new cover.  Thought it was the head.

[dave500]

Forget the gasket maker/silicone/whatever and forget sanding That groove has been butchered by a PO and the only fix is a good used cover

Bryanj, While I feel you're ultimately correct... I'm still going after a safe temporary solution until I source a nice used valve cover.

Is the damage on the cover or the head? Or both??

The damage is strictly on the valve cover.

Is the mating surface uneven or is the groove pitted and deteriorated from corrosion?

The mating surface appears to be fine, the issue is that the groove has been butchered and the gasket no longer fills it, allowing oil to flow into the groove and around the gasket. I like your JB weld idea... seems like a very interesting fix.. Just not sure this cover is worth the effort. +5 bonus points for using the word 'kludge' - one of my favorites for this type of situation. 

id use silicone gasket maker and let it skin over for 45 minutes before you assemble it,no excess should get where it shouldnt then.

This is the route I'm leaning on most heavily at the moment. I can't imagine this stuff breaking down in such a short amount of time that it'd really be dangerous... I intend to actively begin looking for a valve cover, and in fact have found one on eBay currently at around $55 shipped. Dave500, would you put the silicone sealer into the gasket groove essentially filling the pits much the way you would with the JB weld idea, and then lay the gasket into the groove after 45 minutes, or lay the gasket in and then fill the remaining space around it with the sealer?

Thanks again everyone.

dont use the rubber gasket,just fill the groove neatly with silicon so it sits proud of the mating surface like the gasket is supposed to do,let it skin right over for 45 -60 minutes and itll hold,itll be removable aswell,cut the nozzle on a 45 degree about the size of the gasket,work evenly and smoothly to form a nice circular bead around the cover,the new gasket i used on my pan leaked,so after i got sick of wiping up under it when parked i just used a bead in the pans groove in the same way,the supplied gasket was too thin in diameter and had little crush.

[RAFster122s]

+1 on Dave500's method, it will be a good fix and won't have issues with bits breaking off going anywhere. Pick up a new cover when you need to work on the top end again. Dave knows these bikes well.

Save the expense for later and enjoy the bike.

[AMD500]

I know this is an old post, but since I followed the methods outlined hear, I figure it is still a good place to ask the question.

Soooo, I used Dave500's method, because the O ring in my gasket kit was leaving me with oil spot on my pants. After I installed the valve cover (rocker cover), I was about to adjust the tappets when I noticed that some of the liquid gasket had smushed into the tappet area. Not a lot mind you, but enough to notice through the tappet covers. I did my best to remove the excess, but I am still concerned. Can I go ahead, adjust everything and ride happy and care free, or do i need to be worried? What can bits of gasket floating around do? completely F*CK my engine? Should I take everything apart and start over?

Thanks for the input.

[Airborne 82nd]

Yes start over you do not want ANY of that crap floating around. Dave's idea is a good one I let mine sit over night to fully cure did it on my points cover.

[AMD500]

Yeah, I figured. Thanks for your reply! Any advice on getting a good even bead with the sealant? I had a really hard time not making a mess with the stuff.

[Muckinfuss]

I'm a little late to this party, but I'd recommend Permatex or Loctite anaerobic gasket maker over RTV anything.  Auto and Marine OEM's have been using it for years (so have I) so it's well tested.  Pricey.  Two part application....a spray on activator and the gasket material in a tube with a very pointed applicator for absolute control of the bead.  There are red compositions and blue.  I've used both and no one has shared any difference other than color and smell.  It's not going to flake and migrate like RTV can.