Topic: Help! Bike's done and discovered oil leak at valve cover gasket.

[Jayelwin]

So I'm done with my CB750 K5 build and I let it warm up to sync the carbs and noticed oil on the floor. Traced it back to a leak right at the valve cover, right smack dab in the middle at the front just above the well for plug 2 and 3. The screw at that point only holds the top breather cover on - the screws for the valve cover are under the breather cover.

I REALLY REALLY don't want to pull the engine on this now that I'm done. I was wondering if possibly removing all the valve cover screws (some will be hard to get to) and then lifting the valve cover as much as possible and making sure the gasket is lined up properly (I know you can't remove it). Then torquing down the screws again.

Some of these screws are going to be hard to get to - gonna need to get some sort of angled bit to get around the frame rails.

Any advice? Thanks.

[Jayelwin]

Oh, and it's on a new gasket I got from 4into1

[Old Scrambler]

Just as you expected............take it easy...........they should be snug............if all is installed properly, just snug tight when cold..............then re-do after a warm-up.....................I have a few small blocks of wood to hold the cover up while the gasket is aligned.

[DH]

it's been said that Honda mechanics back in the day could flat rate a valve cover gasket without pulling the engine. After removing the valve cover screws and raising the cover as far as possible, cleaning the surface, and maneuvering a new gasket OVER top of the cover, starting at one side, and progressively tucking the gasket underneath while moving to the opposite side. Once you've maneuvered it over the cover, line things up and put the cover bolts back in. I have never done one, but have done 1 piece oil pan gaskets on cars and trucks using the same method with good results.

[Jayelwin]

Do you think I should first try to remove the breather cover and re torque the bolts at the leak point?

[seanbarney41]

I have replaced valve cover gasket with the engine in the frame before.  Here are some tips to help-
1.  You gotta remove the tank of course, and the coils and their brackets.
2.  Get yourself a right angle screwdriver.
3.  If you unhook everything that doesn't flex (like exhaust, airbox, all the engine mounts and bolts) you can sort of rotate  the engine up in back and down in front to gain a little extra room.  This may not be an option if nice new paint is involved.

[Jayelwin]

The gasket is a brand-new gasket, I'm hoping it might just not be laying right and might need to be shifted and then the cover retorqued


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[MCRider]

And remember it is not symetrical. It only goes one way. Be sure you've got it right side up before manipuaitng under the cover.

If you decide to replae it.

[Jayelwin]

It's a fairly brisk leak.

I bought a screw kit and those screws were too long. I trimmed them down but I'm secretly hoping that they're still too long and bottoming out in the head.

[Jayelwin]

I would definitely consider a frame kit - any info or web page to look at?

[754]

The gasket fits over a few dowels, most of it can't move.
 If its just in one spot you can see, try this. Unfortunately valvecover, lift nd hold up with wire or whatever.thengently lift gasket in that leak are

[Henning]

Picture of how I did mine...
To refresh, tank off, coils off, support the valve cover properly so you're not fighting that as well, remember to orient the gasket correctly, and get the genuine Honda gasket. It's quality, and it can handle being massaged over the valve cover (twice, I put it in the wrong way round first).
The bolts for the breather cover are quite long and you might have problems getting them off. I did, but I wasn't too concerned about a bit more patina on the frame. If it is a problem you can follow the advice about removing the engine bolts to get more clearance.

[Jayelwin]

Well I was able to get the breather cover off and the two screws under there were able to be turned more than a quarter turn each pretty easily. Let's hope that stops the leak or I've got more work to do.

[evanphi]

I think I have a leak right in the same place. I'm putting new oil in this week, and I will be keeping a very close eye on the leak this season. May have to do the same thing as Jayelwin!