This Wossner piston kit features a standard 92.00mm bore with a measured diameter of 84.42mm, engineered for Yamaha YFM400FW Kodiak (2000–2006) and YFM4 Grizzly 400 (2007–2008) models. Built for durability and thermal efficiency, this forged piston is optimised for four-stroke engine performance in utility ATV applications.

Features

• 
  

  Forged piston construction for superior strength and reliability

  
  


• 
  

  Advanced heat transfer design from combustion chamber to cylinder walls

  
  


• 
  

  Elliptical profile promotes uniform bearing surface under thermal expansion

  
  


• 
  

  Even thrust load distribution reduces localised stress and prevents piston collapse

  
  


• 
  

  Manufactured in Germany

  
  

Specifications

• 
  

  Bore: 92.00mm

  
  


• 
  

  Diameter: 84.42mm

  
  


• 
  

  Display: 400 cm³

  
  


• 
  

  Stroke: 70.50 mm

  
  


• 
  

  Clearance: 0.08 mm

  
  


• 
  

  Compression Ratio (Wossner): 8.50:1

  
  


• 
  

  Compression Ratio (OEM): 10.50:1

  
  


• 
  

  Dome Volume: -2.90 cm³

  
  


• 
  

  Compression Height: 26.90 mm

  
  


• 
  

  Clips P/N: CW20

  
  


• 
  

  Pin P/N: WP052

  
  


• 
  

  Ring Set P/N: 845XSY

  
  

Cross-Reference OEM Part Numbers

• 
  

  Part No. 56-W9924.00A.WO

  
  


• 
  

  Wossner Piston 8901DA

  
  


• 
  

  5GH-11631-00-00

  
  


• 
  

  40076M08450

  
  

Vehicle Fitments

• 
  

  Yamaha YFM400FW Kodiak 2000–2006

  
  


• 
  

  Yamaha YFM4 Grizzly 400 2007–2008