Here is a NOS Yamaha YZ250 94-95 WR250Z 94-96 STD Piston 4EW-11631-01-D0  NEW OEM. Box was only opened for pics. 

Fitment:

Yamaha Motorcycle 1995 WR250ZG Crankshaft Piston

Yamaha Motorcycle 1994 WR250ZF Crankshaft Piston

Yamaha Motorcycle 1995 YZ250G1 Crankshaft Piston

Yamaha Motorcycle 1993 YZ250E1 Crankshaft Piston

Yamaha Motorcycle 1993 YZ250E Crankshaft Piston

Yamaha Motorcycle 1996 WR250ZH Crankshaft Piston

Yamaha Motorcycle 1997 WR250ZJ Crankshaft Piston

Yamaha Motorcycle 1994 YZ250F1 Crankshaft Piston