Read my post again, slowly and carefully.
I sugested NOT using synthetic for the run-in period.
I also described galling of metal and siezing as possible results of not running in correctly. Some would describe this as "blowing the piston" I suppose.
In addition, when you first get it running, warm it up then ride it for a minute or two, then check the spark plug for a light brown color. If the color is any lighter than that, don't ride until you increase the main jet, a lean mixture will make the engine run hot enough to seize and/or hole the piston.