New engine blows head gasket

[Quilty]

Think I already know the answer to this question but I thought I'd throw it out there anyways.
I put my engine back together after replacing the cylinder sleeves and bearings in both the top and bottom end. I went through the heat cycles that we associate with a new build and retorqued. About 6 miles down the road on the first ride she overheats and the blows a head gasket what could cause this to happen??

 

[TwoManyXS1Bs]

After resleeving the cylinders, they need to be machined flat (skimmed). The head probably needs to be done, too. Then, the lengths of the 2 hollow alignment dowels need to be checked, so that they don't prevent head-to-cylinder headgasket compression.

Also, do a Google Custom Search on "leakless xs assembly". Note the headgasket sealing tricks that accommodate warped heads/cylinders...

 

[Max Midnight]

Here and here

 

[TwoManyXS1Bs]

Good ones, Max. Here's another:

http://www.xs650.com/forum/showthread.php?t=39997

 

[grizld1]

Quilty, the overheating raises a red flag. I hate to suggest this, but did you lose compression and conclude that the loss was caused by a blown gasket rather than a holed piston?

 

[Quilty]

@grizzld When I put it back together and ran through the heat cycles it was fine the I retorqued it after the next set of heat cycles it started to run v lean like there was an air leak somewhere. I couldn't find the leak and I overlooked the head gasket. I suspected that the heads weren't mating properly or faulty gasket. I know for sure that the barrels were flattened then skimmed by the engineer but I can't be certain that the head was. I assumed it was a given that it would be done aswell.
Interesting threads above and I'll look into the no leak thing thanks guys