Piston kit 88.5mm     Wossner 8317D150  
YAMAHA
YZ490 1984 - 1990,
WR500 1992 - 1993,
Wossner forged pistons are superior in strength and design. Engineered to provide the best possible path for combustion chamber heat transfer to cylinder walls. Elliptically designed to provide a more uniform bearing surface under piston heat expansion, eliminating localized pressure and distributing thrust loads more evenly, thereby preventing piston collapse. Made in Germany Part No. 56-W4815.150.WO

Manufacturer Yamaha Kit Part Number 8317 YOM From WR500 ”“ 1992,  YZ490 ”“ 1984 YOM To WR500 ”“ 1993,  YZ490 ”“ 1990 Piston number 8317D150 Bore Size  88.5mm - 8317D150 Stroke 82mm Compression Height 40mm Number of Rings 2 Clip Part Number CW18 Pin Size 18mm Pin Part Number WP042 Cylinders 1 Suits Woss Needle Bearing N1022