Moose Racing High Performance 4-Stroke Piston Kit by CP Pistons Features: · Moose Racing replacement piston w/top end gasket kit · Moose Racing Part # 0910-1106 / CP Pistons Part # MK1011 · Bore: Standard 95mm · Compression ratio: 13.5:1 · High performance piston kit by CP Pistons · Each part has been thoroughly developed and incorporates the latest in cutting edge technology that everyone from the top professional riders to your weekend warrior demands · Moose Racing pistons feature forgings for ultimate strength, minimizing friction, durability, power, and weight reduction · Full radius dome designs maximize quench while eliminating hot spots that promote detonation · Internal bracing maximizes durability while decreasing friction in the pin assembly · Each Moose Racing piston kit includes a high performance piston, wrist pin, rings, circlips, and a top end gasket kit · Made in the USA · Fits 2006-2009 Yamaha YZ450F and 2007-2009 WR450F