Why does my head continue to weep coolant through the studs

[2001KX5]

Well after having my cylinder decked to clean the surface and after getting heli coils put in the threads for the head studs I continue to get some weeping of coolant around some of the head studs.

I'm just wondering if any of you guys had this issue and if you think the cyl. head to frame mount could cause this?

[hughes]

You had the cylinder decked but what about the surface of the head?? Is the coolant leaking between the head and cylinder or is it leaking around the  cylinder head nuts that bolts the head down? What gaskets are you using?

[2001KX5]

Yeah its weeping up through the head studs. I also took one nut off last night and the head stud was actually loose so I can to finger tighten it before I torqued the nut back down.

I never had the head re-surfaced but it was sent to eric gorr with my cylinder plus I checked the surface and its true, plus I ran it over some 1800 grit sand paper on a flat surface before I put it on the last time.

So last night I screwed all the head nuts down until they were fully bottomed and then torqued the whole works down to 22 ft/lbs.

Not sure what impact heli coils have on torque specs, i.e. more than stock needed.   There is no reason in god name for this to be happening. I guess no one else has ever had this problem hey.

I'm using oem kawi head gaskets.  And I always have a backup in my took box.  I'm also using copper spray on the gaskets for extra insurance.

[hughes]

You may need to loctite the studs and use a stud runner to torque them down with. If the studs keep coming loose that's the problem with the coolant leak you loose the clamping force from the nut when the studs back off.

[5dracing]

Just a thought as I read this, check to see that the helicoil is not backing out. If it is sticking up the head may not make proper contact with the cylinder surface allowing seepage.

[2001KX5]

The heli coils are not backing out.  I had them installed and I have the cylinder decked.  Some were not perfectly straight but it don't really cause any issues other than having to watch what I'm doing when I put the head down.

I have tried lock  tight before but I found that it more or less could not stand up to the heat. Perhaps I was using old lock tight or a cheap version.

This doesn't happen right away but after running it for a while it may tend to weep.

I love my kx500 thats why its so frustrating. I rode a cr250 the weekend and it was like riding a honda 50 compared to the 500. I jusy love the power and I don't think I cold ever go back. Unless these issues really piss me off. But at that point I'd prob go go buy and new complete top end and sell my current one.

[hughes]

Use the red loctite 271 it hold up to heat.

[Polar-Bus]

Some were not perfectly straight but it don't really cause any issues other than having to watch what I'm doing when I put the head down.

So you are saying some of your heli-coils are threaded in crooked? This means your studs are crooked, which means your stud nut is not properly seating in the head, and "if" coolant is designed to pass into the head's stud holes, there is your weep. I can't comment for sure, as I have not yet closely seen a KX5 head. Plus its very hard to internet diagnose these types of problems without actually looking right at your engine. I've had 5 KX's in the past 20 years and never seen one weep past a cyl. stud

[hughes]

Some were not perfectly straight but it don't really cause any issues other than having to watch what I'm doing when I put the head down.


Good catch on that one Polar Bus

[2001KX5]

There is no way the coolant system flows through the stud holes in the head. I'm almost positive that the leaking is coming from the studs backing off or vibrating out for what ever reason. This causes a loss of claming force between the cylinder and the head just slightly, but it is enough for it to flow the easiest route out which is through the head studd once it becomes slack.

In any event I'll see how it works out this evening once I get her out for a run. I ran her up last night to operating temp and its fine.

[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.