Yeah both ours cracked down from the holes, we then got new pistons with no holes and tried drilling just one hole (as I recall the first ones has 2 holes). These also cracked. I never ran a ART piston with no hole so can't say if that would of cured it.

Soon after that TYGA started supplying the Wiseco. We started using Wiseco piston but had trouble with the crowns. I moved back to 250's so stopped do any real work after that.
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If I have to take the carbs off once more...