Topic: CB750-Can you replace valve cover gasket with engine in frame?

[russelllowe]

Hi All,

I just wanted to say I had the same problem as the original poster, leaking rocker gasket, and after buying a new one found I couldn't get the valve cover off with the motor in the frame so I could fit it.

Thats when I found this thread, and the advice works perfectly. The gasket opens up quite a large amount without going anywhere near what I think would take to tear it. I opened it up (by giving it a bit of a twist) and started at one end of the cover. At first when I got the first end in I positioned the gasket correctly on the edge and over one of the locating dowels. But when I came to do the other end I found I could use a bit more slack, so went back to the first side and tucked it as far up into the cam box as I could ... Gaining a couple of inches I recon. The second side slipped over easily. Then I went around the whole perimeter to make sure it was in place properly.

All done in less than 5 minutes. I took care not to let the rocker cover force down on the gasket when I was working at the opposite ends (but it's pretty light so there isn't much chance it will crush the twisted gasket unexpectedly). I also removed the tappet covers to give me a little extra room, and less things to catch the gasket on ... but this is probably unnecessary and did expose the gasket to getting caught on the tappets themselves.

It would be fiddley to scrape the gasket surfaces to get them clean, especially at the back around the carbies, but as the previous owner had assembled the engine without using any cover gaskets at all it was easy for me.

I installed the gasket without any sealer and after a few start ups it's not leaking at all.

Cheers, thanks for the advice!

[jpharis]

I have cut frame out and machined fittings to give me access to remove valve cover or top end without removing engine or weakening frame.

[lucky]

Gordon- I hear you!!!  I'd love to know how to not use any sealant as well!!!  I am frustrated with this stupid leak, especially after how long it took to completely rebuild the engine, paint the frame, etc., etc.

And i have a stupid gasket leaking that can't be easily removed...

I just picked up the cover gasket from the dealer...it does appear to be better quality than what came in my "top end gasket kit".  maybe that has something to do with it...all i know is I'm running out of sealant options...just picked up some 1104 instead of Hondabond since it appears to be the sealant of choice.

good luck to you, let me know how it turns out!

Use the original "Gaskacinch" why use the copy cat Honda Bond or YamaBond?

[kghost]

Well the gasket can go on two ways.....only one way will hold oil....

That doesn't address the elephant in the room.....

The 836 kits generate more crankcase pressure that the stock form.

I'm sure someone will disagree...but they do.

I routed my valve cover breather into the Airbox with a 90 degree PCV valve.

This was factory on later 750's ala K7.

No more leaky gaskets with the 836.

[andrewk]

I did notice that the gasket was not perfectly centered around the section of the cover that tightly wraps around the front of the cam chain, on the front center of the cover, right by the cam chain sprocket.  i had a tough time getting the gasket aligned around the inset areas by the #2 and #3 plugs upon reassembly...I did the best  I could without breaking the gasket.

I think this is a clue.  Valve cover gasket probably flipped.

I agree with the need for better crankcase venting for higher compression engines.

I've never used sealant on a clutch cover gasket, and my stuff doesn't leak.  Most of the time the challenge is to not tear the kicker shaft seal.  I keep a handful of those on hand- cheaper and easier to replace that seal than dick with keeping an old one intact that will probably leak later anyway.

Worst part about all that 1104 is the next time you need to service it, another 2 hours of cleanup. I make sure surfaces are clean and flat (flatness is probably the issue with more parts than we all think) and don't use much sealant at all, except in key areas, like pucks, base gasket oil returns, dyno cover grommet, etc. 

[ToryII]

1992 cb750: I dropped my bike on Thursday; it's 2 inches too high for me. It hit the valve cover and began leaking oil. I removed the cover, cleaned everything, placed rtv black on both sides of the gasket, installed everything, and it stopped leaking (for now).

During the install, I placed the gasket on the engine head, then slid the cover on the gasket (was very easy to get gasket in place).

Did you know the benefits of RTV GRAY ?? Everyone should know about rtv gray.

Soon I will buy shorter shocks to lower the bike.

[bryanj]

RTV is the major destroyer of SOHC engines!!!

[ToryII]

I applied a small bead. The glue that was originally used had similar qualities of silicone. Thanks.

[dave500]

RTV is the major destroyer of SOHC engines!!!

good thing tory has a twin cam then?

[Xander^]

is there any way to replace the tachometer gear inside the cam cover without taking the engine off the frame? my tach guage isnt working, the pin from the cam cover is snapped off..