What Causes Air Cooled Head Gaskets To Blow?

I will say good things for ARP as well. I'm sure they have something that will retrofit. I used them on a 2.0 4 cylinder turbo VW running 17-22 pounds of boost with 0 issues.
 
I have also used ARP head studs with great results and that is part of the reason I asked if people were having problems with the stock ones. I'm going to contact them with the specs of the current studs and see if they already produce something that would work. Maybe if it makes sense price wise, and people want them, I could get bunch of them ordered...
 
I have also used ARP head studs with great results and that is part of the reason I asked if people were having problems with the stock ones. I'm going to contact them with the specs of the current studs and see if they already produce something that would work. Maybe if it makes sense price wise, and people want them, I could get bunch of them ordered...

ARP has them on the shelf last time I bought a set. The don't know them as XS650 studs, you have to call with the thread pitch and length. They are $$ though, just plan on that. I run stockers on most of my builds without issue, but if you are running high compression, ARP studs are the way to go.
 
I can't help but wonder what causes them to blow head gaskets

That's where the fire is.

They are 30 years old.

Steel and aluminum have different coefficients of expansion.

Rubber coated sealing washers.

No one ever checked the torque on the head nuts after the initial assembly.

It's a normal engine wear part.

The gasket was built to a price not a standard.

Don't know how informed I am but that should be most of it.
 
That's where the fire is.

They are 30 years old.

Steel and aluminum have different coefficients of expansion.

Rubber coated sealing washers.

No one ever checked the torque on the head nuts after the initial assembly.

It's a normal engine wear part.

The gasket was built to a price not a standard.

Don't know how informed I am but that should be most of it.

Agree 100%
 
So -

I have no problems with my head gasket. Should I re-torque my head to keep it that way, or should I not fix it if it's not broken :)
 
Travis and Hugh,
If either of you were to order some and keep them in stock I'd be more than happy to buy from either of you-- even if the price is slightly higher than going direct.

As to if I actually need them-- I ride a lot of miles and prefer things to be bullet proof. A tow bill to move a bike several hundred miles will pay for a lot of upgrades. Here in Greensboro, towing companies often charge upwards of $100 to move a motorcycle across town and they expect cash. Sure, I can call on Wooley to come out and get me when I'm in town but if I'm 300 miles away and he has to be at work the next morning... Well, he'd do it but I'd rather not ask.
 
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xjwmx;

Its a easy thing to check. Remove the top engine support for access to the inner studs. Use 30 ft-lbs (for the large studs) on the torque wrench, and confirm that none of the acorn nuts rotate. Its been 2 years since my top end re-build, so I'll be checking my torques as soon as the weather gets warmer.
 
I'm not interested in keeping anything in stock from ARP, but Travis might be... Stock is fine, and yes, always check the torque on the head after a rebuild or after a couple of years.

I recommend 35ft Lbs of torque on the large nuts, more than the manual suggests, but I've never once had a problem with head gaskets at that torque.
 
So -

I have no problems with my head gasket. Should I re-torque my head to keep it that way, or should I not fix it if it's not broken :)

I tend to do the re-torque on mine. I didn't retorque one and now it's leaking, coincidence????
 
I'm not interested in keeping anything in stock from ARP, but Travis might be... Stock is fine, and yes, always check the torque on the head after a rebuild or after a couple of years.

I recommend 35ft Lbs of torque on the large nuts, more than the manual suggests, but I've never once had a problem with head gaskets at that torque.
Those studs are machined using low grade soft steel,I wouldn't adventure to far off course from factory torque specs.
 
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