Wossner is Germany's finest aftermarket forged piston and rod manufacturer and have over 25 years of experience in the high-performance racing industry. Top European racers and FIM World Champions rely on Wossner for only the best pistons, rods and customer service.Features In-house designed and manufactured; all forgings are produced in Wossner's company-owned forging operation 4-stroke pistons are made using a double-bridged forging design Lightweight pistons with the tightest piston-wall clearances in the industry give you a quieter running engine All pistons include piston, ring, wrist pin and pin locks Wossner pistons are used by leading Supercross, Arenacross and MX GP teams Made in Germany Specifications Piston Size: 83.43mm Oversize: +0.50mm Replacement Rings: 835XSY Replacement Wrist Pin: WP026 Replacement Circlip: CW19 Fits: Yamaha YFM400 KODIAK 1993-1994 1996-1997 YFM400FW BIG BEAR (SEMI AUTO) 4WD 2007-2010 YFM400FW BIG BEAR 4WD 2002-2004 2006 YFM400FW BIG BEAR 4X4 2000-2001