Namura NA-40015K 70.95mm Top End Repair Kit Fits: Yamaha YFB 250 Timberwolf 2WD 1992-99, YFB 250 Timberwolf 4WD 1994-00, YFM 250 Bear Tracker 1999-04, YFM 250 Bruin 2005-06, YFM 250 Big Bear 2007-09 These include everything you need toget youoperational again; they come withpistons, a top end gasket kit and bearings where needed Features MOS2 (Teflon/Molybdenum) Coated Skirts, a rolled-on application process provides a bond that is 10 times stronger than other spray on coatings for increased heat transfer, reduced friction, and helps eliminate cold seizures Hypereutectic Casting Process provides higher silicon content for reduced expansion rates and additional wear resistance; with an ability to withstand higher cylinder temperatures Anodized Domes increase heat resistance and durability; pistons with anodized domes are 75percent stronger than non-anodized pistons