Are there any aftermarket pistons for the 250 that extend the time between rebuilds? I'm not looking for more power in my bike nor do I care if I loose a little power. I am looking for a piston that I can run In my 250 that will last for a few years without having to worry about rebuilding it. Maybe someone makes a skirted piston for it or something. Does such a thing exist or do I have to continue rebuiling it every year?