This Wossner Piston Kit features a 101mm bore (oversize +1.00) and is specifically designed for Yamaha XTZ660 and select ATV models. Engineered with a forged construction for maximum strength and longevity, this piston delivers precise thermal performance and uniform thrust load distribution. Its elliptical design and superior metallurgy make it ideal for high-performance and heavy-duty applications. Made in Germany.

Features

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  Forged design ensures enhanced durability and strength

  
  


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  Optimised heat transfer from the combustion chamber to cylinder walls

  
  


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  Elliptical profile distributes load evenly and reduces risk of piston collapse

  
  


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  Manufactured in Germany

  
  

Specifications

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  Bore: 101.00 mm

  
  


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  Measured Bore: 100.93 mm

  
  


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  Clearance: 0.07 mm

  
  


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  Compression Ratio: OEM

  
  


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  OEM Compression Ratio: 9.20:1

  
  


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  Dome Volume: -0.30 cm³

  
  


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  Compression Height: 27.00 mm

  
  


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  Display: 660 cm³

  
  


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  Hub Stroke: 84.00 mm

  
  


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  Part No.: 56-W8507+100.WO

  
  


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  Piston Kit Model: 8507D100 (+1.00)

  
  

Vehicle Fitments

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  Yamaha XTZ660 Tenere 1991–1998

  
  


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  Yamaha XTZ660 Raptor 1991–1998

  
  


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  Yamaha YFM660R Raptor 2001–2009

  
  


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  Yamaha YFM660F Grizzly 2001–2009