Piston Kit Ktm125Sx 01-06 01.6220.CCast Piston KitProX piston designs are usually similar to the OEM stock configurations, although sometimes these designs are adjusted whenever the ProX engineers discover an opportunity for increased performance ProX cast pistons are very stable ProX cast pistons are made through gravity casting using aluminum alloy with approximately 18 percent silicon content Silicon plays a vital role in ProXs cast piston manufacturing, as it decreases thermal