Question about head decking??

[400exrider707]

Ok over the winter I did a rebuild on my 400ex with a cam and piston. Since I was pretty much broke during this rebuild process I ordered tusk gaskets figuring I would just give them a shot. Well its been slowly developing a leak. So I yanked it all apart, split the three piece head gasket and spray painted the middle section with high temp paint and replaced it. (Yeah probably wasn't the smartest thing to do I know), and well know its leaking again. Its not like blowing out a lot or anything its just a little build up around the gasket. My question is do you think its just shoddy gaskets or could my head be out of "square"??? Ive heard someone talk about having the head "decked." He said this is to make sure the head is perfectly square so the gasket seals well. Makes sense, but does anyone think I will need to have this done, or thinks that it would be a safe thing to do anyways?? Thanks guys.

[BlueZ440]

Yes have your head decked or whatever is called...I'm having the same issue on my Z...I had a small leak and it ran fine for a few races..Last weekend I blew the headgasket again.

SO I replaced the gasket again and torque the head bolts down to 40lbs..requires 32lbs.. So far so good..But as soon as I get time off from racing I will send my head out to a local machine shop(Head & Block) to get it done..

Also make sure your Head Bolts are replaced..

[wilkin250r]

You typically don't run into a problem unless you have overheated. Excess heat can warp the head, because it doesn't cool down uniformly.

Still, with a proper straight-edge, it's not difficult to check. Right off the bat, I would say most likely the problem is your gasket and not the head. However, I still recommend you check your head for warpage any time you have it apart, whether or not you suspect a problem.

If you're going to tear it down to rebuild it, check the head and cylinder to make sure they are straight. Or, have a shop you trust check the flatness of them. It's typically not terribly expensive to have them machined to true flatness if they are warped.

[400exrider707]

Ok thanks wilkin, I should be able to tell if its flat or not with some sort of a straigh-edge then right? I will be pulling it apart again to put a C&D thin gasket in soon so I will check then. Also common sense tells me that Im going to have to have the head and the cylinder both done right? Thanks again.