Maintenance & Technical > KX500 Original

Why does my head continue to weep coolant through the studs

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hughes:
What did you do?? If you are going to test it tonight did you do anything to the head studs of the bolts???

FIVE-HUNGE:
Not sure of your year machine, Are you missing the locator pins ??
I've had this problem everytime I open the head from the very first time I did the first top end job. I bought the bike new.
 Resurface, new studs, all kinds of gaskets, even had a pro motor builder scratching his head.
My so far (two top ends) remedy - resuface head, stock steel gasket, a thin film of Yamabond 4 around the head and cylinder mating surfaces. tourque to factory spec. I've haven't had any issues yet.. I also don't remove head when replacing the piston. I just slide the cylinder with attached head off as one.
ps - leave head stay as last step, fill with coolant before tourqing head stay to spec. Good luck

2001KX5:
Thanks five-hunge, that was just the response I was looking for.

Like I said before, I think this is all stemming from my head bolts coming loose. Seems like every time I torque them they don't feel "bottomed out" when they hit their required torque, almost feel spongy like - well several of them anyway.

So the yami lube 4 is that the same product as say permatex copper high temp silicone sealant? And did you actually put a skim coat on the head and on the cylinder deck rather than the gasket its self? I've been using the permatex copper spray a gasket but perhaps I'll try the high temp silicone on the cylinder and head just prior to assembly.

This is my plan of action from here:

-get the resurfaced for trueness
-put in all new head studs and nuts
-new oem kawi HG
-silcone or copper gasket spray on hg
-lock tight and torque head studs down to 5lbs and let sit over night to make sure the lock tight has set.
-put on head and tighten down head nuts until they feel  bottomed out, then try to put the desired torque on them and lock tight them also, I have a feeling it could be more than stock, but the whole cylinder has helicoils which can take much more torque than a regular thread, not saying that I will over torque them.
-then I'll fill the coolant and take all the air bubbles out
-then tighten down the upper engine mount.

I certainly hope this solves the problem. Its such a stupid issue but one I don't want to loose the motor over.

Any input on my plan of action would be nice.

KXcam22:
2001,
  Is there a chance one or more of your helicoils are pulling out?  The head nuts cannot become loose so quickly unless the stud is either stretching (fatigued) or pulling out.  I had a similar issue on a head. When torquing it would hit torque but not feel quite right. Then it would loosen off and blow the head gasket.  This went on for months.  I finally discovered that the stud and helicoil were slowly pulling out of the cylinder.  Is this happening on one or more studs?  Which ones come loose?  Cam.

KXcam22:
I forgot one thing.  While your head studs are out it works well to lap the head to the cylinder with valve grinding paste.  If you can get an even grey area you may not need resurfacing.  I ran a watercooled road race bike that used no headgasket, just lapped the head and used a bit of sealant.  It never leaked.  Hope this helps. Cam.

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