HELP! Those stupid "D" things in the valve cover g

hotcam · Post by **hotcam** » Sat Oct 03, 2009 5:42 am

HELP! Those stupid "D" things in the valve cover gasket keep popping
out of place.

I'm using threebond sealant on them and correct torque on the cover
bolts and all.

I've never had trouble before with them but no matter what I do they
just won't stay in place on this FZR with the new gasket.
Other bikes? Fine. This bike, original gasket? Fine (no I don't still have the
original gasket

)

I even replaced the new gasket, with another new one, and it still does it.
Have Yamaha made a bad batch of gaskets? Am I a klutz?

Yoniboi · Post by **Yoniboi** » Sat Oct 03, 2009 6:25 am

I ended up changing the rubbers on the cam-cover bolts. They are what push the cover down. Torquing the bolts makes no difference, as the bolt has a limit only tostop you over-squishing the rubber.

Over time the rubber goes hard and pre-squished so doesn't put the same pressure on the cam-cover.

You could try a thin washer between the rubber on the top of the bolt rather than spend more dosh.

hotcam · Post by **hotcam** » Sat Oct 03, 2009 6:29 am

I thought they might be the culprit too... I forgot to mention I've
put new rubbers on the cam cover bolts after the first failure.

creed12r · Post by **creed12r** » Sat Oct 03, 2009 7:07 am

Ensure the head "half moons" and the gasket are well degreased and clean and the sealant should stick it fine,

I've never had a problem with these parts and usually use "hylomar" gasket sealant, but always ensure the parts are well degreased.

hotcam · Post by **hotcam** » Sat Oct 03, 2009 8:33 am

Hmm, then maybe it's the oil in the head seeping onto the D, I only seem
to have trouble with the left ones... yes I am working with the
bike on the sidestand. I'll let you know how it goes...

sickle44 · Post by **sickle44** » Mon Oct 05, 2009 4:53 pm

Hey Cam,

Think I've stated it before, but all I've ever used is Permatex's "High Tack." As already stated make sure everything is properly degreased and clean and then I spray the hell out of the gasket as well as the underside of the valve cover that's contacting the gasket. Let them both sit for a while and tack up, put the rubber gasket into the valve cover which will now hold on to it when turned upside down, place it in, torque it down and Bob's my uncle?

Hope that helps.

hotcam · Post by **hotcam** » Mon Oct 05, 2009 5:28 pm

I have managed to get the "D" to stay in place by cleaning very
thoroughly with degreaser and contact cleaner, and by using
cyanoacrylate sealant

However the gasket is now so
damaged from popping out of place that there is a small weeping
of oil, I'll have to replace the gasket again

I remember when I first built this engine I had the same problem
on the bench, with it dry and no oil at all, not even residue.
However, I was "precise"
with the sealant, not "generous" with it, so that would not have helped.

I think Yamaha have mis-located or mis-sized the solid
reinforcing inside the "D" in the new series of gaskets.
When the gasket is rested in place on the cam case, without the
cover, the "D" sits proud quite a long way. When the cover is tightened,
you can see a LOT of stress on the "D" so that it bulges inward
(concave) not sitting flat like all the new bikes in the showroom.

When I get the replacement gasket, I might take a bit of a grind
off the contact surface of the "D" (maybe 0.5mm or so) and see
how it sits with a little less compression on it.
Then I'll stick it in place REAL good. I WILL BEAT THIS STUPID PROBLEM.
GRR :angry

hotcam · Post by **hotcam** » Sat Oct 10, 2009 7:25 am

OK I just did a valve adjustment on my Kawasaki 1000GTR.

Damn that was easy. Screw-and-locknut adjusters, no shims to buy
and the cams don't have to come out. All 16 valves adjusted in 2 hours.
The downside is, they need adjustment more often than an EXUP.
20,000km seems to be the absolute longest time, 10,000km check is good.
Exup is 40,000km!

But mainly I can say
THE KAWASAKI VALVE COVER GASKET DIDN'T GIVE ANY TROUBLE.
Despite being pretty much exactly the same design style.

I have ANOTHER new valve cover gasket from Yamaha, this one seems to
be made slightly differently around the Ds? I hope this one works, and I
will be doing some checks and mods to make it work.

But that will have to wait until after the MotoGP which is down here next
weekend.

hotcam · Post by **hotcam** » Sun Oct 25, 2009 12:05 am

OK so I have installed the new valve cover gasket and the cover.

What I did was take the rubber washers off the cover bolts, and
use a bench grinder to make them about 1mm thinner.
That seems to put a lot less strain on the gasket and D's,
while allowing the bolts to be done up to the 'sticking place'
(as William Shakespeare puts it). Looking good so far.

I'll go put the rest of it together now and see how it works.

(edit) seems to not leak at the valve cover now (/edit)

Big Jon · Post by **Big Jon** » Mon Mar 15, 2010 4:20 pm

Just resurrecting an old thread. I had the same issue with 2 yamaha gaskets in a row, both of them popped IN, not out, thus peeling the lip off and killing the gasket. Both times on different sides. Hylomar is a premium sealant but it doesn't work as an adhesive because it never sets up fully. Cheaper sealants with adhesive qualities may be the better way to go, but I think you may be onto something with a run of gaskets with a D portion slightly too big, as it was an issue with the old grommets too.