Slight Oil Leak

[DutchRutter]

Hello fellow CB people!

Its been a while since I posted anything about my 14.
The other day I noticed a small looking oil seep left hand side, toward the top, rear right under the valve cover. I did a search and found that other have had this same leak and it ended up going away on its own.

I cleaned the area in hopes mine would do the same but as of this morning, no dice. I now have fresh oil in that same spot. (kind of hard to see in the picture but its there) just on top of the top cooling fin. I want to say its originating from the valve cover gasket itself, maybe even a little from the gasket nearer the center of the valve cover.



Has anyone replaced the valve cover gasket themselves? Looking at it, I don't think it would be too difficult assuming there is enough space to take it out without pulling the engine. and would there be any other seals etc. needing replaced or just the gasket itself?

[peterbaron]

This was common on '13 models
Very rare on '14 and newer models.
Very little seepage.
A few members have replaced the r/c gasket and applied silicone to afected corners..

[mvk24_imp]

I just opened the valve cover a few days ago to do the 4 small o rings in the PAIR valve system because the new noise was driving me crazy from them leaking.. tank had to come off but it was honestly still pretty tight under there. It would have been more of a project IMO to get the cover off completely instead of just lifting it up to get the o rings/seals out like I did. It's definitely doable but you'll have to remove some more stuff to make some room. I meant to do a write up and forgot, I may just do it on the new cb1100 net site.

Off topic but I took the advice of a 2014 owner on YouTube and added a 1/2 ID x 7/8 OD - 18 gauge machine bushing/washer under my front valve cover bolts to compress the front of the cover down slightly more because there is a surprising gap between the cover and heads where the pair valve seal ends up leaking under load... so I would also replace those 4 small seals/gaskets if you are already taking the cover off.

Personally I would wipe clean along the gasket and check the valve cover bolts to make sure they're evenly tight.

I was surprised to see all of the clamps on the intake boots were loose incidentally when I was checking stuff while I was tinkering.

2014 CB1100, 1981 KZ440 LTD, 1993 Yamaha XJ600 Seca, 1994 Yamaha XJ600 Seca

[peterbaron]

Good write up with pics, mvk

[mvk24_imp]

Good write up with pics, mvk

Thank you, going to try to do it more in order and more detail on the new site if I can remember next week.

Just figured while sort of on the topic I'd let OP know its worth doing while the cover is off

2014 CB1100, 1981 KZ440 LTD, 1993 Yamaha XJ600 Seca, 1994 Yamaha XJ600 Seca

[mattmcuomo@yahoo.com]

Mine have been "weeping" for many miles and years.... I just wipe it clean and continue to ride.

Sent from my Pixel 6 using Tapatalk

[mvk24_imp]

did my14 a few mos ago, same thing, but on left, replaced vc gasket and seals. good opportunity to clean up the frame and under tank. also used the opportunity to tap and block the pair valve ports correctly . used permatex spray adhesive on the top (up side) of the vc gasket to stick it in the valve cover, greased the under side and put it back on. at 10 years a vc gasket leak isn't unexpected really on anything, so i wasn't concerned, but i HATE leaks, or seeps.

Thats a good idea with the spray adhesive I never thought of that.

What did you use to plug the pair? I saw the delete plates online but I actually like the Decel popping sound so I was trying to avoid deleting it entirely. But I will if the noise of a leaking pair valve comes back again lol

2014 CB1100, 1981 KZ440 LTD, 1993 Yamaha XJ600 Seca, 1994 Yamaha XJ600 Seca

[DutchRutter]

Thanks all!

I was looking through the schematics of the valve cover on motosport.com and figured anything rubber should probably get replaced. So I have the gasket, those O-rings and "rubber setting" which looks like they go under those washers that MVK added. I don't think the round chrome plugs would need to be replaced unless they are cracked or broken somehow.
I do agree the leak is very small and could probably just be cleaned up and keep on no problem. But I am also part of the "Cant stand a leak" group. And it gives me a weekend project to tinker on.
It does look like there was some clear sealer applied between that chrome plug and the valve cover gasket, is that normal or maybe a sign that somebody has been in there before and reused the gasket?
Bike now has 22k miles btw, so not a whole lot.

I also thought that it would be worth trying to re torque those VC cover bolts and make sure they aren't loose and causing the leak. I'll probably give that a try this weekend before I order everything up.

[Lord Popgun]

The chrome plug has sealer applied at the factory. The service manual specifies where exactly to apply it.

Check here if you don’t have a manual https://cb1100forum.net/forum/showthread...270#pid270

The link goes to our other CB board.

[mvk24_imp]

I used the spray adhesive on the end plugs as well when i glued it to the VC, then wiped the excess/overspray off w laquer thinner after it was installed on the bike.


I tapped the pair valve port holes int he head with a 1/8 npt tap and put in shallow plugs. to that point, i no longer need the o ring seals there either. I don't like popping. to me popping = exhaust leak (because.. it basically is)

Smart idea

2014 CB1100, 1981 KZ440 LTD, 1993 Yamaha XJ600 Seca, 1994 Yamaha XJ600 Seca